RFR: 8351194: Clean up Hotspot SA after 32-bit x86 removal [v3]

[Kerem Kat]

> Remove 32-bit x86 specific code from the HotSpot Serviceability Agent following the removal of 32-bit x86 support.
> 
> - Removed x86-specific implementations and ifdef blocks.
> - Renamed files with X86 in the name when they are also used from AMD64, e.g. `X86Frame` → `AMD64Frame`.
> - Cleaned up platform detection logic in `PlatformInfo`.
> - Updated documentation references.

Kerem Kat has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:

 - run RotateLeftNode*IdealizationTests on amd64 too
 - Merge branch 'master' into clean-x86-sa-JDK-8351194
 - Merge branch 'master' into clean-x86-sa-JDK-8351194
 - Clean up Hotspot SA after 32-bit x86 removal

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Changes: https://git.openjdk.org/jdk/pull/27844/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27844&range=02
  Stats: 2781 lines in 47 files changed: 623 ins; 2110 del; 48 mod
  Patch: https://git.openjdk.org/jdk/pull/27844.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27844/head:pull/27844

PR: https://git.openjdk.org/jdk/pull/27844