ClassNameTests.testBug152841 fails with Assertion error

In https://download.eclipse.org/eclipse/downloads/drops4/I20241102-1800/testresults/html/org.eclipse.jdt.core.tests.model_ep434I-unit-macosx-aarch64-java17_macosx.cocoa.aarch64_17.html

```
N/A

junit.framework.AssertionFailedError
at junit.framework.Assert.fail(Assert.java:55)
at junit.framework.Assert.assertTrue(Assert.java:22)
at junit.framework.Assert.assertNotNull(Assert.java:256)
at junit.framework.Assert.assertNotNull(Assert.java:248)
at junit.framework.TestCase.assertNotNull(TestCase.java:391)
at org.eclipse.jdt.core.tests.model.ClassNameTests.testBug152841(ClassNameTests.java:1255)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at junit.framework.TestCase.runTest(TestCase.java:177)
at org.eclipse.jdt.core.tests.junit.extension.TestCase.runTest(TestCase.java:970)
at junit.framework.TestCase.runBare(TestCase.java:142)
at junit.framework.TestResult$1.protect(TestResult.java:122)
at junit.framework.TestResult.runProtected(TestResult.java:142)
at junit.framework.TestResult.run(TestResult.java:125)
at junit.framework.TestCase.run(TestCase.java:130)
at junit.framework.TestSuite.runTest(TestSuite.java:241)
at org.eclipse.jdt.core.tests.model.SuiteOfTestCases$Suite.runTest(SuiteOfTestCases.java:114)
at junit.framework.TestSuite.run(TestSuite.java:236)
at org.eclipse.jdt.core.tests.model.SuiteOfTestCases$Suite.superRun(SuiteOfTestCases.java:97)
at org.eclipse.jdt.core.tests.model.SuiteOfTestCases$Suite$1.protect(SuiteOfTestCases.java:85)
at junit.framework.TestResult.runProtected(TestResult.java:142)
at org.eclipse.jdt.core.tests.model.SuiteOfTestCases$Suite.run(SuiteOfTestCases.java:94)
at junit.framework.TestSuite.runTest(TestSuite.java:241)
at junit.framework.TestSuite.run(TestSuite.java:236)
```

Start with the linked Eclipse test-results report and org.eclipse.jdt.core.tests.model.ClassNameTests.testBug152841 at ClassNameTests.java:1255. Run this test in the macOS AArch64 Java 17 environment described by the report, then inspect the assertion and its setup to determine why the expected value is null. Done means the test no longer fails in that environment and the relevant regression coverage remains passing.

Written by the indexing model from the issue text.