RFR: 8343824: Remove unused InstructionFlags in C1

[Thomas Schatzl]

Hi all,

  please review this change that removes unused/unreferenced flags from the `Instruction::InstructionFlag` enum for the C1 compiler.

Testing: gha, tier1-3

Thanks,
  Thomas

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Commit messages:
 - 8343824

Changes: https://git.openjdk.org/jdk/pull/21973/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21973&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343824
  Stats: 10 lines in 1 file changed: 0 ins; 10 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21973.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21973/head:pull/21973

PR: https://git.openjdk.org/jdk/pull/21973