RFR: 8277893: Arraycopy stress tests [v6]

[Aleksey Shipilev]

> I would like to fork the new tests off the JDK-8150730. These tests were instrumental in capturing many bugs in my arraycopy work, and I think they are good on their own merit, because they provide a test for the current baseline and on-going minor improvements in arraycopy on all platforms, not only x86_64, and they might be cleanly backportable.
> 
> A brief tour of these tests:
> 
> - Tests all data types;
> - Tests small arrays exhaustively, which captures conjoint/disjoint cases, errors near the edges, etc;
> - Tests large arrays with fuzzing around powers of two and powers of ten, both conjoint and disjoint cases;
> - Tests all available compilation modes for arraycopy stubs; for example, running on AVX-512 enabled machine runs all versions down to `-XX:UseAVX=0 -XX:UseSSE=0` cases;
> - Tests with/without compressed oops mode -- theoretically only needed for `Object` copies, but Hotspot cobbles together int+coops and long+no-coops loops, so I decided to alternate coops mode for all data types;
> 
> My previous version used individual `@run` clauses for all configurations, but I think the Java driver is cleaner and easier to maintain.
> 
> Test times:
> 
> 
> # x86_64 (TR 3970X)
> real	4m6.192s
> user	52m50.523s
> sys	0m13.755s
> 
> # x86_64 (TR 3970X) -XX:+UseZGC
> real	6m2.573s
> user	72m43.541s
> sys	0m25.697s
> 
> # x86_32 (TR 3970X)
> real	6m56.405s
> user	92m56.377s
> sys	0m6.677s
> 
> # x86_64 (i5-11500)
> real	29m19.024s
> user	103m52.925s
> sys	1m7.175s
> 
> # AArch64 (ThunderX2)
> real	2m59.623s
> user	26m14.624s
> sys	0m9.771s
> 
> 
> Since these tests are quite long, especially on small machines, I hooked them up to `hotspot:tier3`.
> 
> Additional testing:
>  - [x] Linux x86_64 fastdebug `compiler/stress/arraycopy`
>  - [x] Linux x86_32 fastdebug `compiler/stress/arraycopy`
>  - [x] Linux AArch64 fastdebug `compiler/stress/arraycopy`

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Peel out check{Bounds,Conjoint,Disjoint}

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6594/files
  - new: https://git.openjdk.java.net/jdk/pull/6594/files/6789eb8b..bb823dbd

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6594&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6594&range=04-05

  Stats: 31 lines in 1 file changed: 20 ins; 6 del; 5 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6594.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6594/head:pull/6594

PR: https://git.openjdk.java.net/jdk/pull/6594