[jdk21u] Integrated: Merge jdk21:master

[Rob McKenna]

Merge jdk21 into jdk21u

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Commit messages:
 - Merge
 - 8310873: Re-enable locked_create_entry symbol check in runtime/NMT/CheckForProperDetailStackTrace.java for RISC-V
 - 8309502: RISC-V: String.indexOf intrinsic may produce misaligned memory loads
 - Merge
 - 8310171: Bump version numbers for 21.0.1

The merge commit only contains trivial merges, so no merge-specific webrevs have been generated.

Changes: https://git.openjdk.org/jdk21u/pull/7/files
  Stats: 90 lines in 6 files changed: 67 ins; 5 del; 18 mod
  Patch: https://git.openjdk.org/jdk21u/pull/7.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/7/head:pull/7

PR: https://git.openjdk.org/jdk21u/pull/7