Optimize build_jumpdest_map()

[chfast]

Optimize the build_jumpdest_map() procedure by comparing opcode as
signed integer and eliminating always true op <= OP_PUSH32 (0x7f) check.

[chfast]

Benchmarks on Haswell 4.0 GHz, Clang 12.

Comparing o/master to o/opt
Benchmark                                                                Time             CPU      Time Old      Time New       CPU Old       CPU New
-----------------------------------------------------------------------------------------------------------------------------------------------------
baseline/analyse/main/blake2b_huff_mean                               -0.1258         -0.1258             6             5             6             5
baseline/analyse/main/blake2b_shifts_mean                             -0.0770         -0.0770             4             3             4             3
baseline/analyse/main/sha1_divs_mean                                  -0.0848         -0.0848             1             1             1             1
baseline/analyse/main/sha1_shifts_mean                                -0.0725         -0.0725             1             1             1             1
baseline/analyse/main/weierstrudel_mean                               -0.0948         -0.0948             8             7             8             7
baseline/analyse/micro/beginsub_push1s_0xffff_mean                    -0.0397         -0.0397            65            62            65            62
baseline/analyse/micro/beginsubs_0xffff_mean                          -0.2491         -0.2491            33            25            33            25
baseline/analyse/micro/jumpdests_0xffff_mean                          -0.0201         -0.0201            89            87            89            87
baseline/analyse/micro/loop_with_many_jumpdests_mean                  -0.0194         -0.0194            33            33            33            33
baseline/analyse/micro/push1s_0xffff_mean                             -0.0351         -0.0351            68            66            68            66
baseline/analyse/micro/push32s_0xffff_mean                            -0.0375         -0.0375             4             4             4             4
baseline/analyse/micro/zeros_0xffff_mean                              -0.2483         -0.2483            33            25            33            25

[codecov]

Codecov Report

Merging #308 (96ddad5) into master (48964fc) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #308      +/-   ##
==========================================
- Coverage   99.76%   99.76%   -0.01%     
==========================================
  Files          24       24              
  Lines        3832     3831       -1     
==========================================
- Hits         3823     3822       -1     
  Misses          9        9              

Flag	Coverage Δ
consensus	99.17% <100.00%> (-0.01%)	⬇️
unittests	99.76% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
lib/evmone/baseline.cpp	99.82% <100.00%> (-0.01%)	⬇️