[jdk18u] RFR: 8280600: C2: assert(!had_error) failed: bad dominance

[Tobias Hartmann]

Backport of [JDK-8280600](https://bugs.openjdk.java.net/browse/JDK-8280600). Applies cleanly. Approval is pending.

Thanks,
Tobias

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Commit messages:
 - 8280600: C2: assert(!had_error) failed: bad dominance

Changes: https://git.openjdk.java.net/jdk18u/pull/68/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk18u&pr=68&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8280600
  Stats: 54 lines in 2 files changed: 53 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk18u/pull/68.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk18u pull/68/head:pull/68

PR: https://git.openjdk.java.net/jdk18u/pull/68