[SDK] Add benchmark for base2 exponential histogram indexer

[euroelessar]

Updates #1391

Changes

Add benchmark to measure performance of the indexer.

Results from a dev instance:

Run on (16 X 2899.97 MHz CPU s)
CPU Caches:
  L1 Data 48 KiB (x8)
  L1 Instruction 32 KiB (x8)
  L2 Unified 1280 KiB (x8)
  L3 Unified 55296 KiB (x1)
Load Average: 1.00, 0.33, 0.15
-------------------------------------------------------------
Benchmark                   Time             CPU   Iterations
-------------------------------------------------------------
BM_NewIndexer            5.73 ns         5.74 ns    121518000
BM_ComputeIndex/-1       4.09 ns         4.09 ns    171316000
BM_ComputeIndex/0        4.08 ns         4.08 ns    171349000
BM_ComputeIndex/1        8.62 ns         8.63 ns     81330000
BM_ComputeIndex/20       8.60 ns         8.61 ns     81323000

Negative scale has better performance due to using a custom more optimized path.

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[codecov]

Codecov Report

Merging #2181 (f966b99) into main (d980e8b) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2181   +/-   ##
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  Coverage   87.52%   87.52%           
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  Files         169      169           
  Lines        4887     4887           
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  Hits         4277     4277           
  Misses        610      610           

[marcalff]

LGTM, thanks for the contribution.

[lalitb]

LGTM. Thanks

[esigo]

LGTM
Thank :)