RFR: 8318219: RISC-V: C2 ExpandBits [v2]

[Hamlin Li]

> Hi,
> Can you review the change to add intrinsic for ExpandBits for Long & Integer?
> Thanks!
> 
> related to: https://github.com/openjdk/jdk/pull/16481
> 
> ## Test
> ### jtreg
> test/jdk/java/lang/CompressExpand*.java
> test/hotspot/jtreg/compiler/intrinsics/TestBitShuffleOpers.java
> test/hotspot/jtreg/compiler/intrinsics/
> 
> ### gtest
> test/hotspot/gtest/opto/test_compress_expand_bits.cpp

Hamlin Li has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:

 - merge master
 - refine comments and tests
 - enable TestBitShuffleOpers.java
 - Initial commit

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

Changes: https://git.openjdk.org/jdk/pull/16658/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16658&range=01
  Stats: 165 lines in 5 files changed: 162 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/16658.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16658/head:pull/16658

PR: https://git.openjdk.org/jdk/pull/16658