[jdk13u-dev] RFR: 8260704: ParallelGC: oldgen expansion needs release-store for _end

[Olga Mikhaltsova]

I'd like to backport JDK-8260704 to jdk13u for parity with jdk11u.
The original patch applied manually due to the slight context changes. This patch is identical to the same one applied to jdk11u.
All regular tests passed.

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Commit messages:
 - Backport afd5eefdae388a53a0d6bffc2cf94b878ac1881e

Changes: https://git.openjdk.java.net/jdk13u-dev/pull/262/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk13u-dev&pr=262&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8260704
  Stats: 12 lines in 2 files changed: 5 ins; 1 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk13u-dev/pull/262.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk13u-dev pull/262/head:pull/262

PR: https://git.openjdk.java.net/jdk13u-dev/pull/262