RFR: 8304055: G1: Remove OldGCAllocRegion::release

Mon Mar 13 14:07:40 UTC 2023

Simple removing unnecessary code around BOT update in old-gen allocator.

Test: tier1-6

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Commit messages:
 - g1-remove-release

Changes: https://git.openjdk.org/jdk/pull/12999/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12999&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304055
  Stats: 35 lines in 2 files changed: 0 ins; 35 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/12999.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12999/head:pull/12999

PR: https://git.openjdk.org/jdk/pull/12999