[attraction] reduce allocations in HASH action

[constanca-m]

Description

Improves performance on hashing. See:

$ benchstat old.txt new.txt
goos: linux
goarch: amd64
pkg: github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal/attraction
cpu: 11th Gen Intel(R) Core(TM) i7-11800H @ 2.30GHz
                                │   old.txt    │               new.txt                │
                                │    sec/op    │    sec/op     vs base                │
AttrProc_HashRegex/N20_R10-16     1.802µ ± 15%   1.490µ ± 29%  -17.31% (p=0.029 n=10)
AttrProc_HashRegex/N20_R50-16     5.487µ ± 29%   4.662µ ±  5%  -15.02% (p=0.000 n=10)
AttrProc_HashRegex/N2000_R10-16   162.9µ ± 10%   153.0µ ±  6%   -6.12% (p=0.011 n=10)
AttrProc_HashRegex/N2000_R50-16   537.3µ ±  5%   429.1µ ± 79%  -20.14% (p=0.029 n=10)
geomean                           30.50µ         25.99µ        -14.81%

                                │   old.txt    │               new.txt                │
                                │     B/op     │     B/op      vs base                │
AttrProc_HashRegex/N20_R10-16       480.0 ± 0%     288.0 ± 0%  -40.00% (p=0.000 n=10)
AttrProc_HashRegex/N20_R50-16     2.345Ki ± 0%   1.406Ki ± 0%  -40.02% (p=0.000 n=10)
AttrProc_HashRegex/N2000_R10-16   46.91Ki ± 0%   28.14Ki ± 0%  -40.00% (p=0.000 n=10)
AttrProc_HashRegex/N2000_R50-16   234.5Ki ± 0%   140.7Ki ± 0%  -40.00% (p=0.000 n=10)
geomean                           10.49Ki        6.291Ki       -40.01%

                                │   old.txt   │               new.txt               │
                                │  allocs/op  │  allocs/op   vs base                │
AttrProc_HashRegex/N20_R10-16     10.000 ± 0%    6.000 ± 0%  -40.00% (p=0.000 n=10)
AttrProc_HashRegex/N20_R50-16      50.00 ± 0%    30.00 ± 0%  -40.00% (p=0.000 n=10)
AttrProc_HashRegex/N2000_R10-16   1000.0 ± 0%    600.0 ± 0%  -40.00% (p=0.000 n=10)
AttrProc_HashRegex/N2000_R50-16   4.999k ± 0%   2.999k ± 0%  -40.01% (p=0.000 n=10)
geomean                            223.6         134.2       -40.00%

Testing

I added a unit test to make sure there were no breaking changes.