RFR: 8271242: Add Arena regression tests

[Coleen Phillimore]

On Tue, 27 Jul 2021 06:06:40 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> May I please have reviews for these test additions. These are new regression tests for hotspot arenas. We don't have any and it makes sense to have them since this code is fragile and we work on it.
> 
> It also contains some new gtest utility functions which I will use to consolidate some more test coding, mainly in the metaspace gtests (in a future rfe).
> 
> It also comes with a new jtreg gtest launcher for arena tests to test UseMallocOnly mode. As long as we support that, we should test it.
> 
> ---
> 
> tests: 
> - gtests, manually with 32/64 bit and with/without UseMallocOnly
> - GHAs

Looks good.  Thank you for writing these tests.

test/hotspot/gtest/memory/test_arena.cpp line 65:

> 63:   }
> 64:   // Allocate again. The new allocations should have the same position as the 0-sized
> 65:   // first one.

It seems so dangerous to allow zero sized Amalloc.

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Marked as reviewed by coleenp (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4909