RFR: 8331562: G1: Remove API to force allocation of new regions

[Thomas Schatzl]

Hi all,

  this change removes the API to allow forced allocation of new regions in G1. Before region pinning,
G1 would force allocations of new regions beyond the calculated young gen limit while the gclocker had been active.

With region pinning, this forced allocation is not necessary any more.

Depends on #19061.

Testing: local compilation, gha

Hth,
  Thomas

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

Depends on: https://git.openjdk.org/jdk/pull/19061

Commit messages:
 - 8331562

Changes: https://git.openjdk.org/jdk/pull/19062/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19062&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331562
  Stats: 48 lines in 8 files changed: 0 ins; 33 del; 15 mod
  Patch: https://git.openjdk.org/jdk/pull/19062.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19062/head:pull/19062

PR: https://git.openjdk.org/jdk/pull/19062