Convert runtime performance test suite from JUnit3 to JUnit5

[vogella]

This commit converts AllPerfTests.java from JUnit3 to JUnit5:

• Converted from JUnit3 TestCase with suite() method to JUnit5 @Suite/@SelectClasses
• Replaced static Test suite() method with @TestFactory for dynamic performance tests
• Preserved the original behavior for warming up startup tests
• Preserved headless startup test configuration with eclipse.activateRuntimePlugins=false
• Preserved UI performance test integration
• Maintained complex ContentTypePerformanceTest suite behavior via dynamic test execution

The conversion maintains all original test functionality while modernizing to JUnit5:

• BenchPath.class and PreferencePerformanceTest.class are included via @SelectClasses
• Complex performance session tests are handled via @TestFactory and DynamicTest
• Error handling for setup failures is preserved using RuntimeException wrapping

All tests (395) continue to pass after the conversion with 4 skipped tests unchanged from the original behavior.

[github-actions[bot]]

Test Results

 1 920 files   -  27   1 920 suites   - 27   1h 35m 8s ⏱️ - 14m 47s  4 721 tests ±  0   4 696 ✅ ±  0   24 💤 ±0  1 ❌ ±0  14 010 runs   - 153  13 842 ✅  - 153  167 💤 ±0  1 ❌ ±0 

For more details on these failures, see this check.

Results for commit ececae72. ± Comparison against base commit ead5e72a.