AVX-512 4x multi-buffer implementation of Keccakf1600

[pittma]

This PR adds a 4x multi-buffer implementation of Keccakf1600 for AVX-512-capable systems.

Results

Run on an Intel(R) Xeon(R) 6787P system with the command:

$ taskset -c 4 ./tool/bssl speed -filter ML-KEM-512,ML-KEM-768,ML-KEM-1024,SHA3-512,SHA3-384,SHA3-256,SHA3-224,SHAKE-128,SHAKE-256,SHAKE256-x4,MLDSA44,MLDSA65,MLDSA87

(EDIT: updated the numbers below on a release build and with TurboBoost off)

SHA3-224

	keccak1600-avx512vl	main	delta
16	34.8	21.6	61.11%
256	295.9	254.5	16.27%
1350	335.2	280.3	19.59%
8192	362.4	301.7	20.12%
16384	362.9	302.2	20.09%

SHA3-256

	keccak1600-avx512vl	main	delta
16	35.1	12.7	176.38%
256	297.1	168.6	76.22%
1350	335.8	254.2	32.10%
8192	339	278	21.94%
16384	342.2	282.9	20.96%

SHA3-384

	keccak1600-avx512vl	main	delta
16	35	21.6	62.04%
256	205	173.1	18.43%
1350	260.2	217.3	19.74%
8192	262.7	219.2	19.84%
16384	262.9	218.2	20.49%

SHA3-512

	keccak1600-avx512vl	main	delta
16	34.5	21.6	59.72%
256	155.9	131.6	18.47%
1350	179.2	149.8	19.63%
8192	182.6	152.9	19.42%
16384	182.7	152.9	19.49%

SHAKE-128

	keccak1600-avx512vl	main	delta
16	33.4	21	59.05%
256	290.8	249.6	16.51%
1350	369.6	308.7	19.73%
8192	419.9	349.5	20.14%
16384	421.4	350.4	20.26%

SHAKE-256

	keccak1600-avx512vl	main	delta
16	33.5	21	59.52%
256	289.3	250.7	15.40%
1350	334	279.9	19.33%
8192	338.6	282.5	19.86%
16384	341.9	285.1	19.92%

SHAKE-256-x4

Absorb

	keccak1600-avx512vl	main	delta
16	23.5	7.5	213.33%
256	231.5	63.5	264.57%
1350	291.9	70.8	312.29%
8192	303.4	71.4	324.93%
16384	304.7	72	323.19%

Squeeze

	keccak1600-avx512vl	main	delta
16	23.6	7.5	214.67%
256	232.3	63.2	267.56%
1350	302.9	69.9	333.33%
8192	317.8	70.5	350.78%
16384	321.7	71.2	351.83%

ML-KEM

Key Generation

	keccak1600-avx512vl	main	delta
512	100788.1	55436	81.81%
768	66051.9	35364.6	86.77%
1024	50816.2	23842	113.14%

Encap

	keccak1600-avx512vl	main	delta
512	85870.7	50311.3	70.68%
768	59054.7	33292.2	77.38%
1024	44367.8	22340.2	98.60%

Decap

	keccak1600-avx512vl	main	delta
512	66953.9	42214.6	58.60%
768	45659.9	28065.4	62.69%
1024	34363.3	19108.1	79.84%

ML-DSA

Key Generation

	keccak1600-avx512vl	main	delta
44	10747.3	9682.2	11.00%
65	5724.3	5207.3	9.93%
87	4090.9	3644.9	12.24%

Signing

	keccak1600-avx512vl	main	delta
44	2442.8	2363.3	3.36%
65	1542.9	1469.8	4.97%
87	1264.5	1194.6	5.85%

Verify

	keccak1600-avx512vl	main	delta
44	9809.8	8978.4	9.26%
65	6248	5707.7	9.47%
87	3907.3	3526.3	10.80%

Putting in draft mode while I work out FIPS build issues.