RFR: 8290133: JFR: Remove unused methods in Bits.java

[Erik Gahlin]

Could I have a review of PR that removes some unused methods. 

Testing: jdk/jdk/jfr

Thanks
Erik

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Commit messages:
 - Initial

Changes: https://git.openjdk.org/jdk/pull/9457/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9457&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290133
  Stats: 80 lines in 2 files changed: 1 ins; 77 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9457.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9457/head:pull/9457

PR: https://git.openjdk.org/jdk/pull/9457