[lilliput-jdk17u:lilliput] RFR: 8310534: [Lilliput/JDK17] Shenandoah/JVMTI heap-walk crashes

[Roman Kennke]

I observe a crash in JVMTI heap-walk code when running Shenandoah even with -UCOH, see bug report for details.

The fix for now is to revert the relevant change back to clean upstream state. The JVMTI heap-dump would be disabled with +UCOH anyway in #35, and eventually fixed properly by #21.

Testing:
 - [x] serviceability/jvmti/Heap/IterateHeapWithEscapeAnalysisEnabled.java TEST_VM_OPTS="-XX:+UseShenandoahGC"
 - [x] tier1 with TEST_VM_OPTS="-XX:+UseShenandoahGC"

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Commit messages:
 - [Lilliput/JDK17] Shenandoah/JVMTI heap-walk crashes

Changes: https://git.openjdk.org/lilliput-jdk17u/pull/37/files
 Webrev: https://webrevs.openjdk.org/?repo=lilliput-jdk17u&pr=37&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310534
  Stats: 4 lines in 1 file changed: 0 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/lilliput-jdk17u/pull/37.diff
  Fetch: git fetch https://git.openjdk.org/lilliput-jdk17u.git pull/37/head:pull/37

PR: https://git.openjdk.org/lilliput-jdk17u/pull/37