[lilliput-jdk17u:lilliput] RFR: 8299552: [Lilliput/JDK17] Fix 32bit builds

[Roman Kennke]

32bit builds in Lilliput/JDK17 are broken:

* For target hotspot_variant-server_libjvm_objs_space.o:

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Commit messages:
 - Revert unnecessary change
 - Use passed-in thread register in fast_lock/x86_32 instead of fetching the thread again
 - Move owning_thread_from_monitor() back into Threads, and add check for thread being an active JavaThread
 - Add fast_unlock impl in C2 path of x86_32
 - Allow NULL monitor owners
 - Fix race when fetching owning thread outside of STW pause
 - SA fixes for 32 bits
 - More fixes
 - Exclude C2 parts when C2 is not built
 - Exclude C2LoadNKlassStub from 32bit builds
 - ... and 4 more: https://git.openjdk.org/lilliput-jdk17u/compare/a19d9a40...a0eab51d

Changes: https://git.openjdk.org/lilliput-jdk17u/pull/2/files
 Webrev: https://webrevs.openjdk.org/?repo=lilliput-jdk17u&pr=2&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299552
  Stats: 84 lines in 13 files changed: 48 ins; 14 del; 22 mod
  Patch: https://git.openjdk.org/lilliput-jdk17u/pull/2.diff
  Fetch: git fetch https://git.openjdk.org/lilliput-jdk17u pull/2/head:pull/2

PR: https://git.openjdk.org/lilliput-jdk17u/pull/2