RFR: 8325885: GenShen: harmonize with JDK-8325671

[Y. Srinivas Ramakrishna]

/issueJDK-8325885

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Commit messages:
 - Merge branch 'master' into generation_type
 - GLOBAL_GEN -> GLOBAL
 - Merge branch 'master' into generation_type
 - Changes stemming from hanges to upstream for preparing for
 - Build failure.

Changes: https://git.openjdk.org/shenandoah/pull/402/files
 Webrev: https://webrevs.openjdk.org/?repo=shenandoah&pr=402&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325885
  Stats: 87 lines in 16 files changed: 10 ins; 3 del; 74 mod
  Patch: https://git.openjdk.org/shenandoah/pull/402.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah.git pull/402/head:pull/402

PR: https://git.openjdk.org/shenandoah/pull/402