RFR: 8318218: RISC-V: C2 CompressBits

[Hamlin Li]

Hi,
Can you review the change to add intrinsic for CompressBits for Long & Integer?
Thanks!

## Test
pass jtreg test:
test/jdk/java/lang/CompressExpand*.java

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jdk/pull/16481/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16481&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318218
  Stats: 102 lines in 6 files changed: 100 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/16481.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16481/head:pull/16481

PR: https://git.openjdk.org/jdk/pull/16481