RFR: 8319716: RISC-V: Add SHA-2 [v12]

[Robbin Ehn]

> Hi, please consider.
> 
> Main author is @luhenry, I only fixed some minor things and tested it.
> 
> Such as:
> test/hotspot/jtreg/compiler/intrinsics/sha/
> test/jdk/java/security/MessageDigest/
> test/jdk/jdk/security/
> tier1
> 
> And still running some test.

Robbin Ehn has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 21 additional commits since the last revision:

 - Merge branch 'master' into sha256
 - Fixed comment
 - Fixed flags
 - Fixed vlen 128
 - Merge branch 'master' into sha256
 - fixed lmul
 - remove merge, renames
 - Easier reg layout and 128/m2
 - Minor update
 - index store state back
 - ... and 11 more: https://git.openjdk.org/jdk/compare/2838a364...2442b9c6

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16562/files
  - new: https://git.openjdk.org/jdk/pull/16562/files/01105251..2442b9c6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16562&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16562&range=10-11

  Stats: 3353 lines in 268 files changed: 2127 ins; 412 del; 814 mod
  Patch: https://git.openjdk.org/jdk/pull/16562.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16562/head:pull/16562

PR: https://git.openjdk.org/jdk/pull/16562