Improve stability of Java code completion (sealed) tests.

[lahodaj]

No description provided.

[mbien]

could you add those two lines from #8025

netbeans/java/java.completion/test/unit/src/org/netbeans/modules/java/completion/CompletionTestBaseBase.java

Lines 70 to 72 in f7026d4

	// bump tresholds to avoid context dumps from "excessive indexing" warnings
	System.setProperty("org.netbeans.modules.parsing.impl.indexing.LogContext$EventType.PATH.treshold", "100");
	System.setProperty("org.netbeans.modules.parsing.impl.indexing.LogContext$EventType.MANAGER.treshold", "100");

this gets rid of repeated context dumps which make the log hard to read
https://github.com/apache/netbeans/actions/runs/12376205548/job/34543384322?pr=8066#step:10:7086

[mbien]

all green - one test less to worry about. Thanks a lot for stabilizing the completion tests!

[lahodaj]

Lets see how this works (and if it work well enough). If this turns out to work OK, maybe we need to generalize the approach, and use it in other tests that do waitScanFinished.

Thanks for the review!