RFR: 8306482: Remove unused Method AccessFlags

[Coleen Phillimore]

Please review this small change to remove Method AccessFlags that are unused.  These flags were moved to ConstMethod a long time ago.
Tested with tier1-4, SA tests locally

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Commit messages:
 - 8306482: Remove unused Method AccessFlags

Changes: https://git.openjdk.org/jdk/pull/13549/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13549&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306482
  Stats: 27 lines in 4 files changed: 0 ins; 27 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/13549.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13549/head:pull/13549

PR: https://git.openjdk.org/jdk/pull/13549