RFR: 8326975: Parallel: Remove redundant PSOldGen::is_allocated

Wed Feb 28 16:34:58 UTC 2024

Simple removing redundant code, since old-gen should have been allocated in the caller context.

Test: tier1-3

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

Commit messages:
 - pgc-old-gen-is-allocated

Changes: https://git.openjdk.org/jdk/pull/18047/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18047&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8326975
  Stats: 14 lines in 3 files changed: 0 ins; 14 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18047.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18047/head:pull/18047

PR: https://git.openjdk.org/jdk/pull/18047