RFR: 8339783: Implementation of JEP 479: Remove the Windows 32-bit x86 Port [v3]

[Magnus Ihse Bursie]

> This is the implementation of [JEP 479: _Remove the Windows 32-bit x86 Port_](https://openjdk.org/jeps/479).
> 
> This is the summary of JEP 479:
>> Remove the source code and build support for the Windows 32-bit x86 port. This port was [deprecated for removal in JDK 21](https://openjdk.org/jeps/449) with the express intent to remove it in a future release.

Magnus Ihse Bursie has updated the pull request incrementally with two additional commits since the last revision:

 - Use #error for unknown CPU
 - Restore PLATFORM_CHECK_DEPRECATION

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/21744/files
  - new: https://git.openjdk.org/jdk/pull/21744/files/d5280f6d..c6b8771b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21744&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21744&range=01-02

  Stats: 16 lines in 2 files changed: 15 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/21744.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21744/head:pull/21744

PR: https://git.openjdk.org/jdk/pull/21744