RFR: Age objects during degeneration

[Kelvin Nilsen]

We found that not aging during degenerated cycles can cause large amounts of memory (e.g. 15 GB) to accumulate in young-gen when it ought to be promoted to old gen.  This creates serious performance degradation.  This patch allows degenerated cycles to age objects.

-------------

Commit messages:
 - Merge remote-tracking branch 'GitFarmBranch/age-objects-during-degeneration' into age-objects-during-degeneration
 - Allow aging of objects during degenerated cycle

Changes: https://git.openjdk.org/shenandoah/pull/210/files
 Webrev: https://webrevs.openjdk.org/?repo=shenandoah&pr=210&range=00
  Stats: 8 lines in 2 files changed: 2 ins; 5 del; 1 mod
  Patch: https://git.openjdk.org/shenandoah/pull/210.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah pull/210/head:pull/210

PR: https://git.openjdk.org/shenandoah/pull/210