[jdk21u-dev] RFR: 8358534: Bailout in Conv2B::Ideal when type of cmp input is not supported

[Aleksey Shipilev]

Clean bailout from the optimization added in JDK 21. While the patch is fairly recent, it does not come with elevated risk, as it just skips the optimization in the case where the alternative is compiler crash. This crash is seen in real world: https://github.com/adoptium/adoptium-support/issues/1191

Additional testing:
 - [ ] Linux x86_64 server fastdebug, `all`

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Commit messages:
 - Backport 704b5990a750719ca927e156553db7982637e590

Changes: https://git.openjdk.org/jdk21u-dev/pull/1904/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1904&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8358534
  Stats: 5 lines in 1 file changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1904.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1904/head:pull/1904

PR: https://git.openjdk.org/jdk21u-dev/pull/1904