test: migrate TestSourceFragment to JUnit 5

[MartinWitt]

#3919

Change Log

The following bad smells are refactored:

JUnit4-@test

The JUnit 4 @Test annotation should be replaced with JUnit 5 @Test annotation.

JUnit4Assertion

The JUnit4 assertion should be replaced with JUnit5 Assertions.

The following has changed in the code:

JUnit4-@test

• Replaced junit 4 test annotation with junit 5 test annotation in testSourceFragmentField
• Replaced junit 4 test annotation with junit 5 test annotation in testSourcePositionFragment
• Replaced junit 4 test annotation with junit 5 test annotation in testSourceFragmentAddChild
• Replaced junit 4 test annotation with junit 5 test annotation in testSourceFragmentAddChildBeforeOrAfter
• Replaced junit 4 test annotation with junit 5 test annotation in testSourceFragmentWrapChild
• Replaced junit 4 test annotation with junit 5 test annotation in testSourceFragmentWrapChildrenAndSiblings
• Replaced junit 4 test annotation with junit 5 test annotation in testElementSourceFragment_getSourceFragmentOf
• Replaced junit 4 test annotation with junit 5 test annotation in testExactSourceFragments
• Replaced junit 4 test annotation with junit 5 test annotation in testSourceFragmentsOfCompilationUnit
• Replaced junit 4 test annotation with junit 5 test annotation in testSourceFragmentsOfFieldAccess
• Replaced junit 4 test annotation with junit 5 test annotation in testSourceFragmentsOfNewArrayList
• Replaced junit 4 test annotation with junit 5 test annotation in testSourceFragmentsOfNewAnnonymousClass

JUnit4Assertion

• Transformed junit4 assert to junit 5 assertion in testSourceFragmentField
• Transformed junit4 assert to junit 5 assertion in testSourcePositionFragment
• Transformed junit4 assert to junit 5 assertion in testSourceFragmentAddChild
• Transformed junit4 assert to junit 5 assertion in testSourceFragmentAddChildBeforeOrAfter
• Transformed junit4 assert to junit 5 assertion in testSourceFragmentWrapChild
• Transformed junit4 assert to junit 5 assertion in testSourceFragmentWrapChildrenAndSiblings
• Transformed junit4 assert to junit 5 assertion in testElementSourceFragment_getSourceFragmentOf
• Transformed junit4 assert to junit 5 assertion in testSourceFragmentsOfCompilationUnit
• Transformed junit4 assert to junit 5 assertion in assertStartsWith
• Transformed junit4 assert to junit 5 assertion in assertEndsWith
• Transformed junit4 assert to junit 5 assertion in testSourceFragmentsOfFieldAccess
• Transformed junit4 assert to junit 5 assertion in testSourceFragmentsOfNewArrayList
• Transformed junit4 assert to junit 5 assertion in testSourceFragmentsOfNewAnnonymousClass
• Transformed junit4 assert to junit 5 assertion in checkElementFragments
• Transformed junit4 assert to junit 5 assertion in assertGroupsEqual