RFR: 8288047: Accelerate Poly1305 on x86_64 using AVX512 instructions [v22]

[Volodymyr Paprotski]

> Handcrafted x86_64 asm for Poly1305. Main optimization is to process 16 message blocks at a time. For more details, left a lot of comments in `macroAssembler_x86_poly.cpp`.
> 
> - Added new KAT test for Poly1305 and a fuzz test to compare intrinsic and java.
>   - Would like to add an `InvalidKeyException` in `Poly1305.java` (see commented out block in that file), but that conflicts with the KAT. I do think we should detect (R==0 || S ==0) so would like advice please.
> - Added a JMH perf test.
>    - JMH test had to use reflection (instead of existing `MacBench.java`), since Poly1305 is not 'properly' registered with the provider.
> 
> Perf before:
> 
> Benchmark                   (dataSize)  (provider)   Mode  Cnt        Score        Error  Units
> Poly1305DigestBench.digest          64              thrpt    8  2961300.661 ± 110554.162  ops/s
> Poly1305DigestBench.digest         256              thrpt    8  1791912.962 ±  86696.037  ops/s
> Poly1305DigestBench.digest        1024              thrpt    8   637413.054 ±  14074.655  ops/s
> Poly1305DigestBench.digest       16384              thrpt    8    48762.991 ±    390.921  ops/s
> Poly1305DigestBench.digest     1048576              thrpt    8      769.872 ±      1.402  ops/s
> 
> and after:
> 
> Benchmark                   (dataSize)  (provider)   Mode  Cnt        Score        Error  Units
> Poly1305DigestBench.digest          64              thrpt    8  2841243.668 ± 154528.057  ops/s
> Poly1305DigestBench.digest         256              thrpt    8  1662003.873 ±  95253.445  ops/s
> Poly1305DigestBench.digest        1024              thrpt    8  1770028.718 ± 100847.766  ops/s
> Poly1305DigestBench.digest       16384              thrpt    8   765547.287 ±  25883.825  ops/s
> Poly1305DigestBench.digest     1048576              thrpt    8    14508.458 ±     56.147  ops/s

Volodymyr Paprotski has updated the pull request incrementally with one additional commit since the last revision:

  remove early return

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/10582/files
  - new: https://git.openjdk.org/jdk/pull/10582/files/56aed9b1..08ea45e5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10582&range=21
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10582&range=20-21

  Stats: 29 lines in 1 file changed: 13 ins; 14 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/10582.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10582/head:pull/10582

PR: https://git.openjdk.org/jdk/pull/10582