RFR: 8368693: Duplicate methods in vmClasses

[Ashutosh Mehra]

This patch removes some duplicate methods that check if a class is loaded in vmClasses. These methods are already present in the class (generated by the `_VM_CLASS_DECLARE` macro).

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Commit messages:
 - 8368693: Remove duplicate methods in vmClasses

Changes: https://git.openjdk.org/jdk/pull/27503/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27503&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8368693
  Stats: 16 lines in 8 files changed: 0 ins; 6 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/27503.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27503/head:pull/27503

PR: https://git.openjdk.org/jdk/pull/27503