RFR: 8287729: Loom: Check alternative implementation on x86_32

[Aleksey Shipilev]

[JDK-8287496](https://bugs.openjdk.java.net/browse/JDK-8287496) brought in alternative implementation for ports to use. This change tests that x86_32 works well with it, and removes the relevant exclusion lists. JVMTI parts are handled by [JDK-8287726](https://bugs.openjdk.java.net/browse/JDK-8287726).

Additional testing:
 - [x] Linux x86_32 fastdebug, `tier1` (one failure, pre-existing)
 - [x] Linux x86_32 fastdebug, `tier2` (clean)
 - [x] Linux x86_32 fastdebug, `tier3` (a few interesting failures, look pre-existing, beyond the scope of this PR)

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Commit messages:
 - Merge branch 'master' into JDK-8287729-loom-alt-x86-32
 - Fix

Changes: https://git.openjdk.java.net/jdk/pull/8994/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8994&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8287729
  Stats: 68 lines in 2 files changed: 0 ins; 68 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8994.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8994/head:pull/8994

PR: https://git.openjdk.java.net/jdk/pull/8994