RFR: 8377142: Jtreg test gc/shenandoah/oom/TestThreadFailure.java triggers assert(young_reserve + reserve_for_mixed + reserve_for_promo <= old_available + young_available) failed [v2]

[Kelvin Nilsen]

> In ShenandoahGenerationalHeap::compute_old_generation_balance(), adjust old_available and young_available when regions are transferred between young and old generations.

Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:

  Respond to reviewer suggestions

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29621/files
  - new: https://git.openjdk.org/jdk/pull/29621/files/276f170b..67e99178

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29621&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29621&range=00-01

  Stats: 63 lines in 1 file changed: 12 ins; 0 del; 51 mod
  Patch: https://git.openjdk.org/jdk/pull/29621.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29621/head:pull/29621

PR: https://git.openjdk.org/jdk/pull/29621