Migrate org.eclipse.ui.editors.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

 2 913 files  +3   2 913 suites  +3   2h 7m 0s ⏱️ - 5m 53s
 8 166 tests ±0   7 921 ✅ +1  245 💤 ±0  0 ❌  - 1 
23 568 runs  ±0  22 786 ✅ +1  782 💤 ±0  0 ❌  - 1 

Results for commit b861f03. ± Comparison against base commit ca934b3.

This pull request removes 131 and adds 131 tests. Note that renamed tests count towards both.

org.eclipse.jface.text.tests.codemining.CodeMiningTest ‑ testClearCodeMiningTextEditorDecorationIfInInvisibleArea
org.eclipse.jface.text.tests.codemining.CodeMiningTest ‑ testCodeMiningAtEndOfLine
org.eclipse.jface.text.tests.codemining.CodeMiningTest ‑ testCodeMiningOnEmptyLine
org.eclipse.jface.text.tests.codemining.CodeMiningTest ‑ testInlinedAnnotationSupportIsInLinesReturnsValidResultAfterDocumentChange
org.eclipse.ui.editors.tests.CaseActionTest ‑ testMultiSelectionCase
org.eclipse.ui.editors.tests.ChainedPreferenceStoreTest ‑ testChainedStore0
org.eclipse.ui.editors.tests.ChainedPreferenceStoreTest ‑ testChainedStore1
org.eclipse.ui.editors.tests.ChainedPreferenceStoreTest ‑ testChainedStore2
org.eclipse.ui.editors.tests.ChainedPreferenceStoreTest ‑ testChainedStore3
org.eclipse.ui.editors.tests.DocumentProviderRegistryTest ‑ testFindByExtensionInWorkspace
…

EditorsTestSuite CaseActionTest ‑ testMultiSelectionCase
EditorsTestSuite ChainedPreferenceStoreTest ‑ testChainedStore0
EditorsTestSuite ChainedPreferenceStoreTest ‑ testChainedStore1
EditorsTestSuite ChainedPreferenceStoreTest ‑ testChainedStore2
EditorsTestSuite ChainedPreferenceStoreTest ‑ testChainedStore3
EditorsTestSuite CodeMiningTest ‑ testClearCodeMiningTextEditorDecorationIfInInvisibleArea
EditorsTestSuite CodeMiningTest ‑ testCodeMiningAtEndOfLine
EditorsTestSuite CodeMiningTest ‑ testCodeMiningOnEmptyLine
EditorsTestSuite CodeMiningTest ‑ testInlinedAnnotationSupportIsInLinesReturnsValidResultAfterDocumentChange
EditorsTestSuite DefaultStickyLinesProviderTest ‑ testEmptySourceCode
…