RFR: 8292443: Weak CAS VarHandle/Unsafe tests should test always-failing cases

[Aleksey Shipilev]

I noticed that current VarHandle/Unsafe test cases do not test the always-failing cases. Strong CASes do test both always-success and always-failing scenarios, while weak CASes only test spurious-failure tests. We should be also testing always-failing cases for these. Weak CAS can spuriously fail, but it cannot spuriously succeed.

The PR looks large, but the actual changes are in `*.template` files, and the rest is generated from them.

Additional testing:
 - [x] Linux x86_64 fastdebug `java/lang/invoke/VarHandles` and `compiler/unsafe` tests
 - [x]  Linux x86_32 fastdebug `java/lang/invoke/VarHandles` and `compiler/unsafe` tests
 - [ ]  Linux AArch64 fastdebug `java/lang/invoke/VarHandles` and `compiler/unsafe` tests

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Commit messages:
 - Fix

Changes: https://git.openjdk.org/jdk/pull/9892/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9892&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8292443
  Stats: 2926 lines in 46 files changed: 2240 ins; 0 del; 686 mod
  Patch: https://git.openjdk.org/jdk/pull/9892.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9892/head:pull/9892

PR: https://git.openjdk.org/jdk/pull/9892