test: migrate NullParentTest to JUnit 5

[MartinWitt]

#3919

Change Log

The following bad smells are refactored:

Junit4-@before

The JUnit 4 @Before annotation should be replaced with JUnit 5 @BeforeEach annotation.

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 testTargetedAccessNullTarget
• Replaced junit 4 test annotation with junit 5 test annotation in testTargetedExpressionNullTarget
• Replaced junit 4 test annotation with junit 5 test annotation in testAssertNullExpression
• Replaced junit 4 test annotation with junit 5 test annotation in testForLoopNullChildren
• Replaced junit 4 test annotation with junit 5 test annotation in testIfNullBranches
• Replaced junit 4 test annotation with junit 5 test annotation in testLocalVariableNullDefaultExpression
• Replaced junit 4 test annotation with junit 5 test annotation in testFieldNullDefaultExpression
• Replaced junit 4 test annotation with junit 5 test annotation in testReturnNullExpression

Junit4-@before

• Replaced @Before annotation with @BeforeEach at method setup

JUnit4Assertion

• Transformed junit4 assert to junit 5 assertion in testTargetedAccessNullTarget
• Transformed junit4 assert to junit 5 assertion in testTargetedExpressionNullTarget
• Transformed junit4 assert to junit 5 assertion in testAssertNullExpression
• Transformed junit4 assert to junit 5 assertion in testForLoopNullChildren
• Transformed junit4 assert to junit 5 assertion in testIfNullBranches
• Transformed junit4 assert to junit 5 assertion in testLocalVariableNullDefaultExpression
• Transformed junit4 assert to junit 5 assertion in testFieldNullDefaultExpression
• Transformed junit4 assert to junit 5 assertion in testReturnNullExpression