crypto/types: optimize compact bit array one count

[cuonglm]

Description

By using bits.OnesCount8 instead of bitwise operations.

Benchmark result on Apple M1:

name                     old time/op    new time/op    delta
NumTrueBitsBefore/new-8    88.5ns ± 1%     9.1ns ± 0%  -89.68%  (p=0.000 n=10+10)

name                     old alloc/op   new alloc/op   delta
NumTrueBitsBefore/new-8     0.00B          0.00B          ~     (all equal)

name                     old allocs/op  new allocs/op  delta
NumTrueBitsBefore/new-8      0.00           0.00          ~     (all equal)

Fixes #9125

---

Before we can merge this PR, please make sure that all the following items have been
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write a little note why.

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[cuonglm]

cc @odeke-em

[codecov]

Codecov Report

Merging #9216 (0a611f4) into master (f04b5dc) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #9216      +/-   ##
==========================================
- Coverage   60.12%   60.12%   -0.01%     
==========================================
  Files         595      595              
  Lines       37190    37188       -2     
==========================================
- Hits        22361    22359       -2     
  Misses      12848    12848              
  Partials     1981     1981              

Impacted Files	Coverage Δ
crypto/types/compact_bit_array.go	77.39% <100.00%> (-0.39%)	⬇️

[tac0turtle]

utACK

[robert-zaremba]

let's clean the inner loop

[cuonglm]

CI fails because of #9010, TestPaginatedVotesQuery

[cuonglm]

CI fails because of #9010, TestPaginatedVotesQuery

#9223 will fix this.

[cuonglm]

Kindly ping @robert-zaremba @odeke-em

[robert-zaremba]

Thanks, good improvement, and code reduction !

[cuonglm]

Ops, wrong issue reference, should be #9215