RFR: 8352635: Improve inferencing of Float16 operations with constant inputs

[Jatin Bhateja]

This is a follow-up PR#22755 to improve Float16 operations inferencing.

The existing scheme to detect Float16 operations for some operations is based on pattern matching which expects to receive inputs through ConvHF2F IR, this patch extends matching to accept constant floating point inputs within the Float16 value range.

Best Regards,
Jatin

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Commit messages:
 - Adding test points and some constant folding cleanups
 - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8352635
 - Merge branch 'master' of http://github.com/openjdk/jdk into JDK-8352635
 - 8352635: Improve inferencing of Float16 operations with constant inputs

Changes: https://git.openjdk.org/jdk/pull/24179/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24179&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8352635
  Stats: 330 lines in 5 files changed: 199 ins; 75 del; 56 mod
  Patch: https://git.openjdk.org/jdk/pull/24179.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24179/head:pull/24179

PR: https://git.openjdk.org/jdk/pull/24179