RFR: 8320069: RISC-V: Add Zcb instructions [v3]

[Robbin Ehn]

> Hi, this is the instructions for zcb.
> 
> Due to over lack of infrastructure having multiple extension dependent instruction does not fit well.
> Some of these compressed instructions are also missing 1 to 1 mapping, e.g. now we have a compressed not, but the corresponding instruction in uncompressed is still xor.
> I think we need to do some rework here.
> 
> I also I don't like the macro expansion as it hopeless in debugger and 'IDE's (vim+rtags for me).
> (macro stuff was originally done when templates where blacklisted in hotspot)
> 
> And I don't want an option for this, as zcb is coming in hwprobe, if you have compressed on you get them if they are supported (may depend on e.g. zbb).
> 
> I have done some modification since it passed tier1, so I'm running stuff over the weekend.

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 three additional commits since the last revision:

 - Merge branch 'master' into zcb
 - Merge branch 'master' into zcb
 - zcb instruction set

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/17122/files
  - new: https://git.openjdk.org/jdk/pull/17122/files/f0206e57..4fa46f3c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17122&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17122&range=01-02

  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/17122.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17122/head:pull/17122

PR: https://git.openjdk.org/jdk/pull/17122