Introduce SIMD for arm64

[pjbgf]

Introduces a SIMD implementation for the arm64 architecture that is largely based on ARM64 SHA1 and aligns with upstream Go. Extensive comments were added to make it easier to maintain the code going forwards.

The previous non-SIMD implementation was removed, as the SHA1 feature is fairly well supported across modern ARM64 hardware. Keeping both versions in place is not worth the additional complexity.

The check for SHA1 feature is based on github.com/klauspost/cpuid/v2. This is a temporary dependency which will be removed once Go exports the same functionality.

The new arm64 native implementation is ~30% faster and can process ~50% more data, performing better than the cgo alternative:

pkg: github.com/pjbgf/sha1cd/test
                                   │     /tmp/before     │                 /tmp/after                 │
                                   │       sec/op        │       sec/op         vs base                │
CalculateDvMask/generic-2            0.0000005500n ± 64%   0.0000009000n ± 22%  +63.64% (p=0.003 n=10)
CalculateDvMask/native-2             0.0000008500n ± 18%   0.0000009000n ± 22%        ~ (p=1.000 n=10)
CalculateDvMask/cgo-2                 0.000001950n ± 28%    0.000002200n ± 73%        ~ (p=0.170 n=10)
Hash8Bytes/sha1-2                           105.8n ±  5%          105.2n ±  0%   -0.57% (p=0.002 n=10)
Hash8Bytes/sha1cd_native-2                  426.4n ±  0%          298.0n ±  0%  -30.12% (p=0.000 n=10)
Hash8Bytes/sha1cd_generic-2                 539.0n ±  1%          538.5n ±  1%        ~ (p=0.171 n=10)
Hash8Bytes/sha1cd_cgo-2                     1.671µ ±  3%          1.677µ ±  8%        ~ (p=0.955 n=10)
Hash320Bytes/sha1-2                         317.4n ±  1%          318.0n ±  0%        ~ (p=0.323 n=10)
Hash320Bytes/sha1cd_native-2                2.257µ ±  0%          1.483µ ±  1%  -34.29% (p=0.000 n=10)
Hash320Bytes/sha1cd_generic-2               2.938µ ±  1%          2.943µ ±  1%        ~ (p=0.238 n=10)
Hash320Bytes/sha1cd_cgo-2                   3.103µ ±  2%          3.038µ ±  2%   -2.10% (p=0.009 n=10)
Hash1K/sha1-2                               786.1n ±  1%          785.8n ±  1%        ~ (p=1.000 n=10)
Hash1K/sha1cd_native-2                      6.255µ ±  1%          4.033µ ±  0%  -35.53% (p=0.000 n=10)
Hash1K/sha1cd_generic-2                     8.194µ ±  1%          8.218µ ±  0%        ~ (p=0.119 n=10)
Hash1K/sha1cd_cgo-2                         5.856µ ±  1%          5.809µ ±  2%        ~ (p=0.089 n=10)
Hash8K/sha1-2                               5.744µ ±  1%          5.764µ ±  1%        ~ (p=0.739 n=10)
Hash8K/sha1cd_native-2                      48.23µ ±  1%          31.41µ ±  1%  -34.88% (p=0.000 n=10)
Hash8K/sha1cd_generic-2                     63.07µ ±  1%          63.05µ ±  0%        ~ (p=0.481 n=10)
Hash8K/sha1cd_cgo-2                         34.55µ ±  2%          33.83µ ±  3%        ~ (p=0.105 n=10)
HashWithCollision/sha1cd_native-2           7.518µ ±  1%          6.115µ ±  0%  -18.66% (p=0.000 n=10)
HashWithCollision/sha1cd_generic-2          8.793µ ±  1%          8.782µ ±  0%        ~ (p=0.171 n=10)
HashWithCollision/sha1cd_cgo-2              6.591µ ±  1%          6.467µ ±  1%   -1.87% (p=0.004 n=10)
geomean                                     171.9n                162.4n         -5.51%

                                   │ /tmp/before  │              /tmp/after              │
                                   │     B/s      │      B/s       vs base                │
Hash8Bytes/sha1-2                    72.13Mi ± 5%    72.54Mi ± 0%   +0.56% (p=0.001 n=10)
Hash8Bytes/sha1cd_native-2           17.89Mi ± 0%    25.60Mi ± 0%  +43.10% (p=0.000 n=10)
Hash8Bytes/sha1cd_generic-2          14.15Mi ± 1%    14.17Mi ± 1%        ~ (p=0.202 n=10)
Hash8Bytes/sha1cd_cgo-2              4.568Mi ± 3%    4.554Mi ± 8%        ~ (p=0.926 n=10)
Hash320Bytes/sha1-2                  961.3Mi ± 1%    959.6Mi ± 0%        ~ (p=0.247 n=10)
Hash320Bytes/sha1cd_native-2         135.2Mi ± 0%    205.8Mi ± 1%  +52.23% (p=0.000 n=10)
Hash320Bytes/sha1cd_generic-2        103.8Mi ± 1%    103.7Mi ± 1%        ~ (p=0.255 n=10)
Hash320Bytes/sha1cd_cgo-2            98.35Mi ± 2%   100.46Mi ± 2%   +2.15% (p=0.010 n=10)
Hash1K/sha1-2                        1.213Gi ± 1%    1.214Gi ± 1%        ~ (p=1.000 n=10)
Hash1K/sha1cd_native-2               156.1Mi ± 1%    242.2Mi ± 0%  +55.12% (p=0.000 n=10)
Hash1K/sha1cd_generic-2              119.2Mi ± 1%    118.8Mi ± 0%        ~ (p=0.117 n=10)
Hash1K/sha1cd_cgo-2                  166.8Mi ± 1%    168.1Mi ± 2%        ~ (p=0.089 n=10)
Hash8K/sha1-2                        1.328Gi ± 1%    1.324Gi ± 1%        ~ (p=0.739 n=10)
Hash8K/sha1cd_native-2               162.0Mi ± 1%    248.8Mi ± 1%  +53.56% (p=0.000 n=10)
Hash8K/sha1cd_generic-2              123.9Mi ± 1%    123.9Mi ± 0%        ~ (p=0.481 n=10)
Hash8K/sha1cd_cgo-2                  226.1Mi ± 2%    230.9Mi ± 3%        ~ (p=0.109 n=10)
HashWithCollision/sha1cd_native-2    81.19Mi ± 1%    99.83Mi ± 0%  +22.96% (p=0.000 n=10)
HashWithCollision/sha1cd_generic-2   69.42Mi ± 1%    69.50Mi ± 0%        ~ (p=0.196 n=10)
HashWithCollision/sha1cd_cgo-2       92.60Mi ± 1%    94.38Mi ± 1%   +1.92% (p=0.004 n=10)
geomean                              114.8Mi         127.0Mi       +10.62%