RFR: 8330071: GenShen: Allow old to expand again at end of each GC

[Kelvin Nilsen]

This corrects errors in the implementations of max_size_for(OLD) and min_size_for(OLD).  These errors were preventing expansion of OLD in preparation for subsequent mixed-evacuation cycles.

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Commit messages:
 - Change behavior of max_old and min_old
 - Merge branch 'openjdk:master' into master
 - Make satb-mode Info logging less verbose
 - Merge branch 'openjdk:master' into master
 - Merge branch 'openjdk:master' into master
 - Revert "Round LAB sizes down rather than up to force alignment"
 - Round LAB sizes down rather than up to force alignment
 - Revert "Remove dead code for inelastic plabs"
 - Remove dead code for inelastic plabs

Changes: https://git.openjdk.org/shenandoah/pull/421/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah&pr=421&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8330071
  Stats: 6 lines in 1 file changed: 4 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/shenandoah/pull/421.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah.git pull/421/head:pull/421

PR: https://git.openjdk.org/shenandoah/pull/421