test: migrate ExecutableRefTest 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 methodTest
• Replaced junit 4 test annotation with junit 5 test annotation in constructorTest
• Replaced junit 4 test annotation with junit 5 test annotation in testGetActualClassTest
• Replaced junit 4 test annotation with junit 5 test annotation in testSameTypeInConstructorCallBetweenItsObjectAndItsExecutable
• Replaced junit 4 test annotation with junit 5 test annotation in testOverridingMethod

JUnit4Assertion

• Transformed junit4 assert to junit 5 assertion in methodTest
• Transformed junit4 assert to junit 5 assertion in constructorTest
• Transformed junit4 assert to junit 5 assertion in testGetActualClassTest
• Transformed junit4 assert to junit 5 assertion in testSameTypeInConstructorCallBetweenItsObjectAndItsExecutable
• Transformed junit4 assert to junit 5 assertion in getInvocationFromMethod
• Transformed junit4 assert to junit 5 assertion in testOverridingMethod