RFR: 8357944: Remove unused CollectedHeap::is_maximal_no_gc

[Albert Mingkun Yang]

Removing effectively dead code/API for all GCs except G1.

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Commit messages:
 - remove-heap-api

Changes: https://git.openjdk.org/jdk/pull/25482/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25482&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8357944
  Stats: 51 lines in 12 files changed: 0 ins; 50 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25482.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25482/head:pull/25482

PR: https://git.openjdk.org/jdk/pull/25482