RFR: 8325991: Accelerate Poly1305 on x86_64 using AVX2 instructions [v4]

[Srinivas Vamsi Parasa]

> The goal of this PR is to accelerate the Poly1305 algorithm using AVX2 instructions (including IFMA) for x86_64 CPUs.
> 
> This implementation is directly based on the AVX2 Poly1305 hash computation as implemented in Intel(R) Multi-Buffer Crypto for IPsec Library (url: https://github.com/intel/intel-ipsec-mb/blob/main/lib/avx2_t3/poly_fma_avx2.asm)

Srinivas Vamsi Parasa has updated the pull request incrementally with one additional commit since the last revision:

  remove unused uniions and fix uses_vl

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/17881/files
  - new: https://git.openjdk.org/jdk/pull/17881/files/6d97c53a..f1b18567

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17881&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17881&range=02-03

  Stats: 33 lines in 2 files changed: 0 ins; 27 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/17881.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17881/head:pull/17881

PR: https://git.openjdk.org/jdk/pull/17881