RFR: JDK-8287671: Adjust ForceGC to invoke System::gc fewer times for negative case

[Xue-Lei Andrew Fan]

On Fri, 3 Jun 2022 18:05:52 GMT, Mandy Chung <mchung at openjdk.org> wrote:

> This reapplies JDK-8287384 and adjust the number of GCs for negative case, i.e. the condition is never met that is used to verify a reference is not GC'ed.

Marked as reviewed by xuelei (Reviewer).

@mlchung Thank you for pick up and fix the issue.

The waiting time now is reduced from 10 seconds to 1 seconds.  As most of the tests intermittent fail, the failure may be more popular now.  Alternatively, it might be OK to run less cases in UnloadingTest.java (for example one or two call to tryUnload() in one test by separating the case into a few).  But let's see if the intermittent failure is still rare enough.

-------------

PR: https://git.openjdk.java.net/jdk/pull/9021