RFR: JDK-8312049: runtime/logging/ClassLoadUnloadTest can be improved

[Doug Simon]

On Thu, 13 Jul 2023 18:28:31 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> Trivial improvements, mainly not spawning individual child processes for every call to `checkFor` and `checkAbsent`. Runtime goes down from 14s -> 10s. We could reduce the runtime a lot more by splitting up the test but I avoided that.
> 
> Checked manually on x64 Linux.

Marked as reviewed by dnsimon (Committer).

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PR Review: https://git.openjdk.org/jdk/pull/14876#pullrequestreview-1529139055