RFR: 8335930: GenShen: Reserve regions within each generation's freeset until available is sufficient

[Kelvin Nilsen]

Reserve regions until available memory within each generation's partition is sufficient to satisfy reserve request.

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Commit messages:
 - Reserve until available in partition is sufficient
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Revert "Change behavior of max_old and min_old"
 - ... and 9 more: https://git.openjdk.org/shenandoah/compare/d2102347...b226b32a

Changes: https://git.openjdk.org/shenandoah/pull/457/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah&pr=457&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8335930
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/shenandoah/pull/457.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah.git pull/457/head:pull/457

PR: https://git.openjdk.org/shenandoah/pull/457