[jdk20u] RFR: 8300823: UB: Compile::_phase_optimize_finished is initialized too late

[Tobias Hartmann]

Backport of [JDK-8300823](https://bugs.openjdk.java.net/browse/JDK-8300823). Applies cleanly. Approval is pending.

Thanks,
Tobias

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Commit messages:
 - 8300823: UB: Compile::_phase_optimize_finished is initialized too late

Changes: https://git.openjdk.org/jdk20u/pull/30/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk20u&pr=30&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8300823
  Stats: 13 lines in 1 file changed: 6 ins; 6 del; 1 mod
  Patch: https://git.openjdk.org/jdk20u/pull/30.diff
  Fetch: git fetch https://git.openjdk.org/jdk20u.git pull/30/head:pull/30

PR: https://git.openjdk.org/jdk20u/pull/30