RFR: 8204868: java/util/zip/ZipFile/TestCleaner.java still fails with "cleaner failed to clean zipfile."

[Jaikiran Pai]

Can I please get a review of this test-only change which proposes to address an intermittent failure in the `test/jdk/java/util/zip/ZipFile/TestCleaner.java` test?

This test does operations on Inflater/Deflater/ZipFile and  closes those instances and then waits for GC to kick in. After wait for a second, it then checks that the underlying resources held by these instances have been cleaned (by the Cleaner).

Once in a while, we have noticed that this test fails because the resources haven't been cleaned. I suspect this is because within the (fixed) 1 second wait time, the Cleaner hasn't yet invoked the cleaning action for these instances.

The commit in this PR updates the test to run it in `othervm` so that the Cleaner actions aren't delayed by any other test or code that might have previously run on the `agentvm`. Furthermore, the test is also updated to the use the `ForceGC` test util which takes into account the jtreg test timeout factor for deciding how long to wait for the Cleaner to initiate the cleaning action. Our CI is configured with a timeout factor of 4, so with this change, instead of a fixed maximum 1 second wait time, the test will now wait a maximum of 4 seconds for the cleaner action to be invoked.

The test continues to pass with this change, even with a repeat execution of 50 runs.

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

Commit messages:
 - 8204868: java/util/zip/ZipFile/TestCleaner.java still fails with "cleaner failed to clean zipfile."

Changes: https://git.openjdk.org/jdk/pull/23742/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23742&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8204868
  Stats: 44 lines in 1 file changed: 21 ins; 11 del; 12 mod
  Patch: https://git.openjdk.org/jdk/pull/23742.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23742/head:pull/23742

PR: https://git.openjdk.org/jdk/pull/23742