RFR: 8292407: Improve Weak* VarHandle tests resilience under spurious failures

[Vladimir Kempik]

On Tue, 16 Aug 2022 08:23:11 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> We have a few reports that existing Weak* VarHandle tests are still flaky, for example on large AArch64 machines or small RISC-V machines.
> 
> The flakiness is intrinsic to the nature of Weak* operations under tests, that can spuriously fail. The last attempt to fix these was [JDK-8155739](https://bugs.openjdk.org/browse/JDK-8155739). We need to strengthen these a bit more.
> 
> The actual values depend on the successful testing on known-failing platforms. I ballparked bumping the attempts 5x and introducing the delay would help without exploding test time in worst cases.

Will test on hifive. and let you know the results, meanwhile, can you include these tests into your patch? , they fail with similar symptoms:

hotspot/jtreg/compiler/unsafe/JdkInternalMiscUnsafeAccessTest*.java

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PR: https://git.openjdk.org/jdk/pull/9889