Payara 6: migrate all test cases to use JUnit 5 #9782
Description
As discussed during tech hour, lets try to add another large chunk breaking change in the 6.0 release (that's what major releases are for... 😉): lets transition all test classes from JUnit 4 to JUnit 5.
This mostly requires replacing the imports. It will require adapting "Before" and "After" annotations, as the naming changes in J5. If we do have some kind of Rule or other JUnit 4 specific constructs, these would be replaces with the JUnit 5 equivalents.
In case some J4 test looks out for exceptions, this needs to be refactored, too - J5 has assertThrows now.