RFR: 8253275: Remove unused methods after CMS removal

[Aleksey Shipilev]

Static analysis shows a few examples of methods that are not used/implemented after CMS removal. We can purge them.

Testing: text searches over the code base, no hits; Linux x86_64 builds

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Commit messages:
 - 8253275: Remove unused methods after CMS removal

Changes: https://git.openjdk.java.net/jdk/pull/219/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=219&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253275
  Stats: 12 lines in 2 files changed: 0 ins; 12 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/219.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/219/head:pull/219

PR: https://git.openjdk.java.net/jdk/pull/219