RFR: 8254805: compiler/debug/TestStressCM.java is still failing

Fri Oct 16 07:09:19 UTC 2020

Use the code motion trace produced by `TraceOptoPipelining` (excluding traces of stubs) to assert that two compilations
with the same seed cause `StressLCM` and `StressGCM` to take the same randomized decisions. Previously, the entire
output produced by `PrintOptoStatistics` was used instead, which has shown to be too fragile. Also, disable inlining in
both `TestStressCM.java` and the similar `TestStressIGVN.java` to prevent flaky behavior, and run both tests for ten
different seeds to improve coverage.

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Commit messages:
 - 8254805: compiler/debug/TestStressCM.java is still failing

Changes: https://git.openjdk.java.net/jdk/pull/693/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=693&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8254805
  Stats: 34 lines in 2 files changed: 21 ins; 3 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/693.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/693/head:pull/693

PR: https://git.openjdk.java.net/jdk/pull/693