[jdk26u] RFR: Merge jdk:jdk26

[Nibedita Jena]

Merge

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

Commit messages:
 - Merge remote-tracking branch 'jdk/jdk26' into Merge_12-30
 - 8374233: Overloaded constructor MountUnmountDisabler(jthread thread) is missed
 - 8371948: TestStackOverflowDuringInit.java fails xss too small on linux-aarch64
 - 8373502: C2 SuperWord: speculative check uses VPointer variable was pinned after speculative check, leading to bad graph
 - 8373110: jstack --mixed frames are broken on macOS after JDK-8371194
 - 8373525: C2: assert(_base == Long) failed: Not a Long
 - 8373246: JDK-8351842 broke native debugging on Linux
 - 8373946: Synth ProgressBarUI implementation confuses background painting with border painting
 - 8373630: r18_tls should not be modified on Windows AArch64
 - 8373552: ExactConversionsSupport: bad JLS links in javadoc
 - ... and 16 more: https://git.openjdk.org/jdk26u/compare/0cd8c8ef...4b08d9c6

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

Changes: https://git.openjdk.org/jdk26u/pull/7/files
  Stats: 3076 lines in 113 files changed: 2201 ins; 430 del; 445 mod
  Patch: https://git.openjdk.org/jdk26u/pull/7.diff
  Fetch: git fetch https://git.openjdk.org/jdk26u.git pull/7/head:pull/7

PR: https://git.openjdk.org/jdk26u/pull/7