fix(chain): use correct gas price during state sync finalization

[bowenwang1996]

As mentioned in #3277, there is an inconsistency in gas price usage during state sync finalization, which can cause the state to diverge if gas price changes between sync block and its prev block.
Fixes #3277.

Test plan

test_catchup_gas_price_change.

[gitpod-io]

[codecov]

Codecov Report

Merging #3278 into master will decrease coverage by 0.01%.
The diff coverage is 98.57%.

@@            Coverage Diff             @@
##           master    #3278      +/-   ##
==========================================
- Coverage   87.06%   87.04%   -0.02%     
==========================================
  Files         217      217              
  Lines       42325    42393      +68     
==========================================
+ Hits        36851    36903      +52     
- Misses       5474     5490      +16     

Impacted Files	Coverage Δ
chain/chain/src/chain.rs	88.61% <50.00%> (+0.16%)	⬆️
chain/client/tests/process_blocks.rs	91.19% <100.00%> (+1.09%)	⬆️
neard/tests/stake_nodes.rs	85.66% <0.00%> (-12.11%)	⬇️
chain/client/src/test_utils.rs	81.32% <0.00%> (-3.71%)	⬇️
chain/network/tests/routing.rs	98.75% <0.00%> (-1.25%)	⬇️
chain/chain/src/test_utils.rs	91.29% <0.00%> (-0.93%)	⬇️
chain/client/src/client_actor.rs	84.86% <0.00%> (-0.30%)	⬇️
chain/chain/src/validate.rs	90.32% <0.00%> (ø)
chain/client/src/sync.rs	88.80% <0.00%> (+0.12%)	⬆️
... and 11 more

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