RFR: 8319716: RISC-V: Add SHA-2

[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.

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Commit messages:
 - SHA-2

Changes: https://git.openjdk.org/jdk/pull/16562/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16562&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8319716
  Stats: 1015 lines in 5 files changed: 1009 ins; 1 del; 5 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