Fix syncParticipantReward rounding issue

[twoeths]

Motivation

This rounding issue was found in random spec tests (altair v1.1.0-beta.3), since that PR is not ready I make the fix a separate one.

Description

Use Math.floor() to calculate syncParticipantReward

This is a follow up PR for #3044

[codeclimate]

Code Climate has analyzed commit 7392437 and detected 0 issues on this pull request.

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[codecov]

Codecov Report

Merging #3055 (e889306) into master (e5af6a4) will not change coverage.
The diff coverage is n/a.

❗ Current head e889306 differs from pull request most recent head 7392437. Consider uploading reports for the commit 7392437 to get more accurate results

@@           Coverage Diff           @@
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  Coverage   59.88%   59.88%           
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  Files         376      376           
  Lines        8926     8926           
  Branches     1318     1318           
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  Hits         5345     5345           
  Misses       3202     3202           
  Partials      379      379           

[github-actions]

Performance Report

✔️ no performance regression detected

Full benchmark results

Benchmark suite	Current: e889306	Previous: e5af6a4	Ratio
BeaconState.hashTreeRoot - No change	754.00 ns/op	714.00 ns/op	1.06
BeaconState.hashTreeRoot - 1 full validator	76.964 us/op	67.786 us/op	1.14
BeaconState.hashTreeRoot - 32 full validator	1.0287 ms/op	927.24 us/op	1.11
BeaconState.hashTreeRoot - 512 full validator	12.676 ms/op	12.073 ms/op	1.05
BeaconState.hashTreeRoot - 1 validator.effectiveBalance	76.170 us/op	63.826 us/op	1.19
BeaconState.hashTreeRoot - 32 validator.effectiveBalance	1.0414 ms/op	827.81 us/op	1.26
BeaconState.hashTreeRoot - 512 validator.effectiveBalance	9.6530 ms/op	8.3945 ms/op	1.15
BeaconState.hashTreeRoot - 1 balances	68.194 us/op	61.182 us/op	1.11
BeaconState.hashTreeRoot - 32 balances	572.95 us/op	508.13 us/op	1.13
BeaconState.hashTreeRoot - 512 balances	5.0067 ms/op	4.7288 ms/op	1.06
BeaconState.hashTreeRoot - 250000 balances	103.65 ms/op	90.321 ms/op	1.15
processSlot - 1 slots	55.660 us/op	40.060 us/op	1.39
processSlot - 32 slots	2.7032 ms/op	2.1823 ms/op	1.24
getCommitteeAssignments - req 1 vs - 250000 vc	5.3858 ms/op	5.2403 ms/op	1.03
getCommitteeAssignments - req 100 vs - 250000 vc	7.4544 ms/op	7.1653 ms/op	1.04
getCommitteeAssignments - req 1000 vs - 250000 vc	8.5787 ms/op	7.7309 ms/op	1.11
computeProposers - vc 250000	24.701 ms/op	22.144 ms/op	1.12
computeEpochShuffling - vc 250000	192.87 ms/op	194.59 ms/op	0.99
getNextSyncCommittee - vc 250000	412.41 ms/op	360.69 ms/op	1.14
altair processBlock - 250000 vs - 7PWei normalcase	107.87 ms/op	93.639 ms/op	1.15
altair processBlock - 250000 vs - 7PWei worstcase	290.00 ms/op	233.01 ms/op	1.24
altair processEpoch - pyrmont_e62330	451.52 ms/op	424.43 ms/op	1.06
pyrmont_e62330 - altair beforeProcessEpoch	65.984 ms/op	83.325 ms/op	0.79
pyrmont_e62330 - altair processJustificationAndFinalization	161.58 us/op	68.251 us/op	2.37
pyrmont_e62330 - altair processInactivityUpdates	74.316 ms/op	65.959 ms/op	1.13
pyrmont_e62330 - altair processRewardsAndPenalties	67.199 ms/op	58.763 ms/op	1.14
pyrmont_e62330 - altair processRegistryUpdates	15.566 us/op	5.9450 us/op	2.62
pyrmont_e62330 - altair processSlashings	5.7150 us/op	1.6900 us/op	3.38
pyrmont_e62330 - altair processEth1DataReset	5.1290 us/op	1.4830 us/op	3.46
pyrmont_e62330 - altair processEffectiveBalanceUpdates	14.197 ms/op	8.4877 ms/op	1.67
pyrmont_e62330 - altair processSlashingsReset	34.187 us/op	10.688 us/op	3.20
pyrmont_e62330 - altair processRandaoMixesReset	41.373 us/op	18.606 us/op	2.22
pyrmont_e62330 - altair processHistoricalRootsUpdate	6.4220 us/op	1.8030 us/op	3.56
pyrmont_e62330 - altair processParticipationFlagUpdates	49.761 ms/op	45.866 ms/op	1.08
pyrmont_e62330 - altair processSyncCommitteeUpdates	4.2690 us/op	1.2800 us/op	3.34
pyrmont_e62330 - altair afterProcessEpoch	130.93 ms/op	121.24 ms/op	1.08
altair processInactivityUpdates - 250000 normalcase	225.99 ms/op	200.21 ms/op	1.13
altair processInactivityUpdates - 250000 worstcase	220.33 ms/op	204.86 ms/op	1.08
altair processParticipationFlagUpdates - 250000 anycase	116.82 ms/op	111.31 ms/op	1.05
altair processRewardsAndPenalties - 250000 normalcase	136.46 ms/op	110.73 ms/op	1.23
altair processRewardsAndPenalties - 250000 worstcase	150.14 ms/op	123.06 ms/op	1.22
altair processSyncCommitteeUpdates - 250000	482.37 ms/op	409.04 ms/op	1.18
Tree 40 250000 create	584.38 ms/op	589.67 ms/op	0.99
Tree 40 250000 get(125000)	284.03 ns/op	273.75 ns/op	1.04
Tree 40 250000 set(125000)	1.7293 us/op	1.7003 us/op	1.02
Tree 40 250000 toArray()	44.461 ms/op	41.651 ms/op	1.07
Tree 40 250000 iterate all - toArray() + loop	45.279 ms/op	41.613 ms/op	1.09
Tree 40 250000 iterate all - get(i)	114.05 ms/op	106.96 ms/op	1.07
MutableVector 250000 create	22.662 ms/op	24.956 ms/op	0.91
MutableVector 250000 get(125000)	13.623 ns/op	12.904 ns/op	1.06
MutableVector 250000 set(125000)	688.60 ns/op	655.81 ns/op	1.05
MutableVector 250000 toArray()	8.3978 ms/op	8.2176 ms/op	1.02
MutableVector 250000 iterate all - toArray() + loop	9.1402 ms/op	8.8458 ms/op	1.03
MutableVector 250000 iterate all - get(i)	3.8109 ms/op	3.7949 ms/op	1.00
Array 250000 create	6.1985 ms/op	5.7469 ms/op	1.08
Array 250000 clone - spread	2.9434 ms/op	2.2170 ms/op	1.33
Array 250000 get(125000)	1.0250 ns/op	1.1320 ns/op	0.91
Array 250000 set(125000)	1.0690 ns/op	1.1130 ns/op	0.96
Array 250000 iterate all - loop	150.80 us/op	167.85 us/op	0.90
aggregationBits - 2048 els - readonlyValues	305.48 us/op	237.29 us/op	1.29
aggregationBits - 2048 els - zipIndexesInBitList	62.973 us/op	47.116 us/op	1.34
ssz.Root.equals	1.7800 us/op	1.3910 us/op	1.28
ssz.Root.equals with valueOf()	2.0160 us/op	1.5860 us/op	1.27
byteArrayEquals with valueOf()	2.0430 us/op	1.5920 us/op	1.28
phase0 processBlock - 250000 vs - 7PWei normalcase	16.188 ms/op	11.951 ms/op	1.35
phase0 processBlock - 250000 vs - 7PWei worstcase	107.47 ms/op	78.106 ms/op	1.38
phase0 afterProcessEpoch - 250000 vs - 7PWei	242.98 ms/op	220.73 ms/op	1.10
phase0 beforeProcessEpoch - 250000 vs - 7PWei	662.20 ms/op	545.44 ms/op	1.21
phase0 processEpoch - mainnet_e58758	939.35 ms/op	788.85 ms/op	1.19
mainnet_e58758 - phase0 beforeProcessEpoch	435.08 ms/op	397.36 ms/op	1.09
mainnet_e58758 - phase0 processJustificationAndFinalization	116.12 us/op	62.543 us/op	1.86
mainnet_e58758 - phase0 processRewardsAndPenalties	163.03 ms/op	86.916 ms/op	1.88
mainnet_e58758 - phase0 processRegistryUpdates	99.754 us/op	52.816 us/op	1.89
mainnet_e58758 - phase0 processSlashings	5.1930 us/op	1.3230 us/op	3.93
mainnet_e58758 - phase0 processEth1DataReset	5.0040 us/op	1.2350 us/op	4.05
mainnet_e58758 - phase0 processEffectiveBalanceUpdates	9.7862 ms/op	9.6187 ms/op	1.02
mainnet_e58758 - phase0 processSlashingsReset	30.137 us/op	8.5140 us/op	3.54
mainnet_e58758 - phase0 processRandaoMixesReset	40.085 us/op	14.503 us/op	2.76
mainnet_e58758 - phase0 processHistoricalRootsUpdate	6.7830 us/op	1.3390 us/op	5.07
mainnet_e58758 - phase0 processParticipationRecordUpdates	28.408 us/op	9.0170 us/op	3.15
mainnet_e58758 - phase0 afterProcessEpoch	215.65 ms/op	198.35 ms/op	1.09
phase0 processEffectiveBalanceUpdates - 250000 normalcase	10.661 ms/op	11.455 ms/op	0.93
phase0 processEffectiveBalanceUpdates - 250000 worstcase 0.5	3.2537 s/op	2.6885 s/op	1.21
phase0 processRegistryUpdates - 250000 normalcase	100.32 us/op	59.771 us/op	1.68
phase0 processRegistryUpdates - 250000 badcase_full_deposits	6.7672 ms/op	5.0722 ms/op	1.33
phase0 processRegistryUpdates - 250000 worstcase 0.5	3.2908 s/op	2.7445 s/op	1.20
phase0 getAttestationDeltas - 250000 normalcase	34.578 ms/op	36.130 ms/op	0.96
phase0 getAttestationDeltas - 250000 worstcase	33.510 ms/op	35.304 ms/op	0.95
phase0 processSlashings - 250000 worstcase	39.548 ms/op	35.379 ms/op	1.12
shuffle list - 16384 els	14.238 ms/op	13.481 ms/op	1.06
shuffle list - 250000 els	186.79 ms/op	195.74 ms/op	0.95
getPubkeys - index2pubkey - req 1000 vs - 250000 vc	2.8922 ms/op	2.5969 ms/op	1.11
getPubkeys - validatorsArr - req 1000 vs - 250000 vc	461.34 us/op	447.27 us/op	1.03
getPubkeys - persistent - req 1000 vs - 250000 vc	17.280 us/op	16.404 us/op	1.05
BLS verify - blst-native	2.1235 ms/op	1.8592 ms/op	1.14
BLS verifyMultipleSignatures 3 - blst-native	4.1108 ms/op	3.8124 ms/op	1.08
BLS verifyMultipleSignatures 8 - blst-native	9.6140 ms/op	8.2153 ms/op	1.17
BLS verifyMultipleSignatures 32 - blst-native	34.592 ms/op	29.812 ms/op	1.16
BLS aggregatePubkeys 32 - blst-native	45.803 us/op	40.101 us/op	1.14
BLS aggregatePubkeys 128 - blst-native	186.49 us/op	156.37 us/op	1.19
getAttestationsForBlock	91.207 ms/op	84.335 ms/op	1.08
CheckpointStateCache - add get delete	22.380 us/op	18.336 us/op	1.22
validate gossip signedAggregateAndProof - struct	4.9999 ms/op	4.4760 ms/op	1.12
validate gossip signedAggregateAndProof - treeBacked	5.1210 ms/op	4.3925 ms/op	1.17
validate gossip attestation - struct	2.4016 ms/op	2.0987 ms/op	1.14
validate gossip attestation - treeBacked	2.4487 ms/op	2.0835 ms/op	1.18

by benchmarkbot/action