[jdk11u-dev] RFR: 8252853: AArch64: gc/shenandoah/TestVerifyJCStress.java fails intermittently with C1

[Aleksey Shipilev]

Unclean backport, because the context is a bit different (StoreVal -> IU renaming already happened). 

Additional testing:
 - [x] Affected test still passes on AArch64, x86_64
 - [ ] `hotspot_gc_shenandoah` passes on AArch64

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Commit messages:
 - Backport 4fb1980fd0539230fdc310aad63bbda8cb1725e6

Changes: https://git.openjdk.java.net/jdk11u-dev/pull/260/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=260&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8252853
  Stats: 16 lines in 2 files changed: 6 ins; 7 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/260.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/260/head:pull/260

PR: https://git.openjdk.java.net/jdk11u-dev/pull/260