RFR: 8322150: [GenShen] TestPeriodicGC fails with "Generational mode: Should have periodic young GC in logs"

[Y. Srinivas Ramakrishna]

8322150: [GenShen] TestPeriodicGC fails with "Generational mode: Should have periodic young GC in logs"

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Commit messages:
 - Merge branch 'master' into should_unload_classes
 - JDK-8322150 should_unload_classes should return true only if a metaspace

Changes: https://git.openjdk.org/shenandoah/pull/372/files
 Webrev: https://webrevs.openjdk.org/?repo=shenandoah&pr=372&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8322150
  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/shenandoah/pull/372.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah.git pull/372/head:pull/372

PR: https://git.openjdk.org/shenandoah/pull/372