[lworld] RFR: [lworld] Run compiler/valhalla/inlinetypes/TestAcmpWithUnstableIf.java without StressUnstableIfTraps until JDK-8367244 is fixed

[Christian Hagedorn]

`compiler/valhalla/inlinetypes/TestAcmpWithUnstableIf.java` crashes when run with `StressUnstableIfTraps` in the CI ([JDK-8367244](https://bugs.openjdk.org/browse/JDK-8367244)).

To reduce the noise in the CI, I'm temporarily passing `-XX:-StressUnstableIfTraps` to disable the stress mode.

Thanks,
Christian

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Commit messages:
 - [lworld] Run TestAcmpWithUnstableIf.java without StressUnstableIfTraps until JDK-8367244 is fixed

Changes: https://git.openjdk.org/valhalla/pull/1635/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1635&range=00
  Stats: 5 lines in 1 file changed: 3 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/valhalla/pull/1635.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1635/head:pull/1635

PR: https://git.openjdk.org/valhalla/pull/1635