RFR: 8306123: Move InstanceKlass writeable flags

[Coleen Phillimore]

Please review this patch to move the writeable Klass AccessFlags to InstanceKlassFlags.
Tested with tier1-4.

-------------

Commit messages:
 - 8306123: Move InstanceKlass writeable flags

Changes: https://git.openjdk.org/jdk/pull/13515/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13515&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306123
  Stats: 114 lines in 6 files changed: 64 ins; 34 del; 16 mod
  Patch: https://git.openjdk.org/jdk/pull/13515.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13515/head:pull/13515

PR: https://git.openjdk.org/jdk/pull/13515