[jdk11u-dev] RFR: 8277893: Arraycopy stress tests

[Aleksey Shipilev]

Clean backport to improve arraycopy testing.

Additional testing:
 - [x] Linux x86_64 fastdebug, `hotspot_compiler_arraycopy`
 - [ ] Linux x86_32 fastdebug, `hotspot_compiler_arraycopy`
 - [ ] Linux AArch64 fastdebug, `hotspot_compiler_arraycopy`

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Commit messages:
 - 8277893: Arraycopy stress tests

Changes: https://git.openjdk.org/jdk11u-dev/pull/1175/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1175&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8277893
  Stats: 1169 lines in 12 files changed: 1168 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1175.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1175/head:pull/1175

PR: https://git.openjdk.org/jdk11u-dev/pull/1175