RFR: 8344960: RISC-V: fix TestFloatConversionsVectorNaN for COH and AlignVector

[Hamlin Li]

Hi,
Can you help to review this patch?
Some background: COH change the header size of an object (from 12 to 8) when compress klass headers is on, this invalidate some of the alignment check in SLP, so the fix is to disable the IR checks when either UseCompactObjectHeaders or AlignVector is on.
It's a follow-up of JDK-8343827 and JDK-8340010 on riscv.

Thanks

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Commit messages:
 - initial commit

Changes: https://git.openjdk.org/jdk/pull/22363/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22363&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8344960
  Stats: 28 lines in 1 file changed: 23 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/22363.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22363/head:pull/22363

PR: https://git.openjdk.org/jdk/pull/22363