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

[Albert Mingkun Yang]

On Thu, 16 Oct 2025 10:05:08 GMT, Kerem Kat <krk at openjdk.org> wrote:

> 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.

Marked as reviewed by ayang (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/27844#pullrequestreview-3344499070