RFR: 8318218: RISC-V: C2 CompressBits [v4]

[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

Hamlin Li 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 five additional commits since the last revision:

 - Remove redundant check
 - Merge branch 'master' into compress-bits
 - Match Op_CompressBits based on UseRVV only
 - remove the new vm option, using Matcher::match_rule_supported instead; move code to riscv_v.ad and C2_MacroAssembler
 - Initial commit

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16481/files
  - new: https://git.openjdk.org/jdk/pull/16481/files/b5eed0ec..3b256e25

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16481&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16481&range=02-03

  Stats: 27499 lines in 621 files changed: 14092 ins; 5448 del; 7959 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