RFR: 8351149: Remove dead IA32/X32/!AMD64 code blocks after 32-bit x86 removal

[Anton Seoane Ampudia]

This PR carries out cleanup of `IA32`-, `X32`- and `!AMD64`-guarded code blocks after the removal of the 32-bit x86 architecture from HotSpot.

These code blocks are either not needed anymore or the guards redundant.

Please note that this changeset addresses the "complement" of [JDK-8351159](https://github.com/openjdk/jdk/pull/27987). This is to say, this PR targets all directories that are *not* `cpu/x86` and `os_cpu/x86`.

**Testing:** passes tiers 1-3

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Commit messages:
 - X32
 - IA32

Changes: https://git.openjdk.org/jdk/pull/27990/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27990&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8351149
  Stats: 210 lines in 22 files changed: 0 ins; 185 del; 25 mod
  Patch: https://git.openjdk.org/jdk/pull/27990.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27990/head:pull/27990

PR: https://git.openjdk.org/jdk/pull/27990