Migrate org.eclipse.e4.ui.tests from JUnit4 to JUnit5

[vogella]

• Convert @RunWith(Suite.class) to @suite
• Convert @Suite.SuiteClasses to @SelectClasses
• Update imports from org.junit.runners to org.junit.platform.suite.api
• Add org.junit.jupiter.api and org.junit.platform.suite.api to Import-Package

[github-actions]

Test Results

 2 940 files  +  471   2 940 suites  +471   2h 37m 5s ⏱️ + 1h 10m 47s
 8 170 tests +    4   7 921 ✅ ±    0  249 💤 +  4  0 ❌ ±0 
23 580 runs  +2 469  22 786 ✅ +2 229  794 💤 +240  0 ❌ ±0 

Results for commit 0ae01d0. ± Comparison against base commit 1fa29c8.

This pull request removes 988 and adds 992 tests. Note that renamed tests count towards both.

org.eclipse.e4.ui.tests.application.Bug299755Test ‑ testBug299755
org.eclipse.e4.ui.tests.application.Bug308220Test ‑ testBug308220
org.eclipse.e4.ui.tests.application.Bug320857Test ‑ testBug320857
org.eclipse.e4.ui.tests.application.E4ResourceTest ‑ bug_leak_517124
org.eclipse.e4.ui.tests.application.EModelServiceFindTest ‑ testBug314685
org.eclipse.e4.ui.tests.application.EModelServiceFindTest ‑ testFindAddons
org.eclipse.e4.ui.tests.application.EModelServiceFindTest ‑ testFindElementsCombinations
org.eclipse.e4.ui.tests.application.EModelServiceFindTest ‑ testFindElementsIdOnly
org.eclipse.e4.ui.tests.application.EModelServiceFindTest ‑ testFindElementsTagsOnly
org.eclipse.e4.ui.tests.application.EModelServiceFindTest ‑ testFindElementsTypeOnly
…

UIAllTests AreaRendererTest ‑ testMultipleStacksUnderTheAreaCreateACTabFolder
UIAllTests AreaRendererTest ‑ testStackInsideMCompositePartDoesNotCreateACTabFolder
UIAllTests Bug299755Test ‑ testBug299755
UIAllTests Bug308220Test ‑ testBug308220
UIAllTests Bug308317Test ‑ testBug308317
UIAllTests Bug320857Test ‑ testBug320857
UIAllTests CompositePartClosingTest ‑ test_partClosing
UIAllTests ContextTest ‑ testOneContext
UIAllTests ContextTest ‑ testThreeContexts
UIAllTests ContextTest ‑ testTwoContexts
…

This pull request removes 7 skipped tests and adds 11 skipped tests. Note that renamed tests count towards both.

org.eclipse.e4.ui.tests.workbench.MWindowTest ‑ TODOtestWindow_X
org.eclipse.e4.ui.tests.workbench.MWindowTest ‑ TODOtestWindow_Y
org.eclipse.e4.ui.tests.workbench.ModelAssemblerTests ‑ testFragments_existingXMIID_checkExists
org.eclipse.e4.ui.tests.workbench.PartFocusTest ‑ Unknown test
org.eclipse.e4.ui.tests.workbench.PartRenderingEngineTests ‑ TODOtestBug326175_True
org.eclipse.e4.ui.tests.workbench.SWTPartRendererTest ‑ Unknown test
org.eclipse.e4.ui.workbench.renderers.swt.MenuManagerRendererTest ‑ testMMenu_ToBeRendered

UIAllTests MWindowTest ‑ TODOtestWindow_X
UIAllTests MWindowTest ‑ TODOtestWindow_Y
UIAllTests MenuManagerRendererTest ‑ testMMenu_ToBeRendered
UIAllTests ModelAssemblerTests ‑ testFragments_existingXMIID_checkExists
UIAllTests PartRenderingEngineTests ‑ TODOtestBug326175_True
org.eclipse.e4.ui.tests.workbench.PartFocusTest ‑ XXXtestNoFocusChangeOnExplicitWidgetSelection
org.eclipse.e4.ui.tests.workbench.PartFocusTest ‑ testFocusChangesOnExplicitPartActivation
org.eclipse.e4.ui.tests.workbench.PartFocusTest ‑ testNoActivationOnExplicitInPartWidgetSelection
org.eclipse.e4.ui.tests.workbench.SWTPartRendererTest ‑ testSetCSSInfo
org.eclipse.e4.ui.tests.workbench.SWTPartRendererTest ‑ testSetCSSInfoWhenNoCSSStylingEngineInContext
…