[master] RFR: 8314863: [Lilliput] Revert changes in zRelocate, prevent ZGC with Lilliput

[Roman Kennke]

The additions of SuspendibleThreadSet in [zRelocate.cpp](https://builds.shipilev.net/patch-openjdk-lilliput/src/hotspot/share/gc/z/zRelocate.cpp.udiff.html) can cause deadlocks. This problem can not easily be solved without major work in Lilliput. Let's revert those changes and prevent usage of ZGC together with Lilliput.

Testing:
 - [ ] hotspot_gc +UCOH
 - [ ] hotspot_gc -UCOH (default)

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Commit messages:
 - 8314863: [Lilliput] Revert changes in zRelocate, prevent ZGC with Lilliput

Changes: https://git.openjdk.org/lilliput/pull/107/files
 Webrev: https://webrevs.openjdk.org/?repo=lilliput&pr=107&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314863
  Stats: 14 lines in 2 files changed: 9 ins; 5 del; 0 mod
  Patch: https://git.openjdk.org/lilliput/pull/107.diff
  Fetch: git fetch https://git.openjdk.org/lilliput.git pull/107/head:pull/107

PR: https://git.openjdk.org/lilliput/pull/107