[11u] RFR: 8227041: runtime/memory/RunUnitTestsConcurrently.java has a memory leak

[Langer, Christoph]

Hi,

please review backport of this test fix.

Bug: https://bugs.openjdk.java.net/browse/JDK-8227041
Webrev: http://cr.openjdk.java.net/~clanger/webrevs/8227041.11u-dev.0/

The test is a real resource drain and causes OOMs - while not really testing something useful. It was already removed in jdk/jdk - so requesting to remove it from JDK11u as well (to fix sporadic test failures).

In jdk11 the relevant source files look a bit different, so I had to modify the original changeset a bit.

Thanks
Christoph