[jdk20u] RFR: 8299959: C2: CmpU::Value must filter overflow computation against local sub computation

[Tobias Hartmann]

Backport of [JDK-8299959](https://bugs.openjdk.java.net/browse/JDK-8299959). Applies cleanly. Approval is pending.

Thanks,
Tobias

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

Commit messages:
 - 8299959: C2: CmpU::Value must filter overflow computation against local sub computation

Changes: https://git.openjdk.org/jdk20u/pull/35/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk20u&pr=35&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299959
  Stats: 72 lines in 2 files changed: 69 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk20u/pull/35.diff
  Fetch: git fetch https://git.openjdk.org/jdk20u.git pull/35/head:pull/35

PR: https://git.openjdk.org/jdk20u/pull/35