Several test failures in JavadocBugsCompletionModelTest in the latest I build I20250225-1800

The report is here: https://download.eclipse.org/eclipse/downloads/drops4/I20250225-1800/testresults/html/org.eclipse.jdt.core.tests.model_ep435I-unit-linux-x86_64-java21_linux.gtk.x86_64_21.html

And one of such similar failing tests is:
```
Completion proposals are not correct!. ----------- Expected ------------ Object[TYPE_REF]{Object, java.lang, Ljava.lang.Object;, null, null, [197, 200], 54} ------------ but was ------------ ---------------------- ---------- expected:<[Object[TYPE_REF]{Object, java.lang, Ljava.lang.Object;, null, null, [197, 200], 54}]> but was:<[]>

junit.framework.ComparisonFailure: Completion proposals are not correct!.
----------- Expected ------------
Object[TYPE_REF]{Object, java.lang, Ljava.lang.Object;, null, null, [197, 200], 54}
------------ but was ------------

---------------------- ----------
expected:<[Object[TYPE_REF]{Object, java.lang, Ljava.lang.Object;, null, null, [197, 200], 54}]> but was:<[]>
at org.eclipse.jdt.core.tests.junit.extension.TestCase.assertStringEquals(TestCase.java:265)
at org.eclipse.jdt.core.tests.junit.extension.TestCase.assertEquals(TestCase.java:240)
at org.eclipse.jdt.core.tests.model.AbstractJavadocCompletionModelTest.assertResults(AbstractJavadocCompletionModelTest.java:283)
at org.eclipse.jdt.core.tests.model.AbstractJavadocCompletionModelTest.assertSortedResults(AbstractJavadocCompletionModelTest.java:253)
at org.eclipse.jdt.core.tests.model.JavadocBugsCompletionModelTest.testBug139621e(JavadocBugsCompletionModelTest.java:918)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
```

These tests passed in the previous build since which we didn't have any changes going in. I suspect these are something to do with the set up or something transient at play here. I see them pass locally, although admittedly it's not the same OS.