RFR: 8244297: Provide utility for testing for memory leaks [v11]

[Kevin Rushforth]

On Wed, 28 Oct 2020 09:47:32 GMT, Florian Kirmaier <fkirmaier at openjdk.org> wrote:

>> It's based on the discussion of my previous PR: https://github.com/openjdk/jfx/pull/71
>> 
>> I Added test utility class copied from JMemoryBuddy and used it to simplify 4 of the existing unit tests.
>> 
>> It's a direct copy of my project [JMemoryBuddy](https://github.com/Sandec/JMemoryBuddy) without any changes.
>> I'm also using it in most of the projects I'm involved with and in my experience, the tests with this Library are very stable. I can't remember wrong test results. Sometimes the memory behaviour of some libraries itself is not stable but the tests with JMemoryBuddy are basically always correct.
>
> Florian Kirmaier has updated the pull request incrementally with one additional commit since the last revision:
> 
>   JDK-8244297
>   more improvements based on code-review

Looks good!

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Marked as reviewed by kcr (Lead).

PR: https://git.openjdk.java.net/jfx/pull/204