Migrate team tests to JUnit 5 #903

[HeikoKlare]

Migrates the tests in org.eclipse.team.tests.core to JUnit 5.

• Exchange JUnit 4 test annotations
• Replace JUnit 4 test suites with JUnit platform suites
• Replace JUnit 4 WorkspaceTestRule with JUnit 5 WorkspaceResetExtension
• Replace JUnit 4 assertions with JUnit 5 assertions

Contributes to https://github.com/eclipse-platform/eclipse.platform/issues/903

[github-actions[bot]]

Test Results

 1 734 files  ±0   1 734 suites  ±0   1h 25m 29s :stopwatch: - 2m 1s  3 973 tests ±0   3 951 :white_check_mark: ±0   22 :zzz: ±0  0 :x: ±0  12 516 runs  ±0  12 355 :white_check_mark: ±0  161 :zzz: ±0  0 :x: ±0 

Results for commit 942a4f21. ± Comparison against base commit 860ec50c.

This pull request removes 21 and adds 21 tests. Note that renamed tests count towards both.

``` AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testFileModificationValidator AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testGetProviderById AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testGetProviderGeneric AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testIsShared AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testLinkFailure AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testLinkSuccess AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testMapFailure AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testMapSuccess AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testMoveDeleteHook AllTeamTests org.eclipse.team.tests.core.RepositoryProviderTests ‑ testMoveDeleteHookBetweenProjects … ``` ``` AllTeamTests AllTeamRegressionTests Bug_217673 ‑ test AllTeamTests AllTeamRegressionTests DoNotRemoveTest ‑ testBug312217 AllTeamTests AllTeamRegressionTests DoNotRemoveTest ‑ test_Utils_updateLabels AllTeamTests RepositoryProviderTests ‑ testFileModificationValidator AllTeamTests RepositoryProviderTests ‑ testGetProviderById AllTeamTests RepositoryProviderTests ‑ testGetProviderGeneric AllTeamTests RepositoryProviderTests ‑ testIsShared AllTeamTests RepositoryProviderTests ‑ testLinkFailure AllTeamTests RepositoryProviderTests ‑ testLinkSuccess AllTeamTests RepositoryProviderTests ‑ testMapFailure … ```

:recycle: This comment has been updated with latest results.