RFR: 8351149: Remove dead IA32/X32/!AMD64 code blocks after 32-bit x86 removal [v2]

[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

Anton Seoane Ampudia has updated the pull request incrementally with one additional commit since the last revision:

  Apply review comments (restore mistakenly cleaned define)

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27990/files
  - new: https://git.openjdk.org/jdk/pull/27990/files/e36fc5ac..a26d83f9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27990&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27990&range=00-01

  Stats: 12 lines in 1 file changed: 12 ins; 0 del; 0 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