Maven/Gradle-JUnit Integration: Support nested and toplevel non-public tests and stabiize result extraction

[matthiasblaesing]

JUnit allows to declare tests on nested (NestedClass2 and DoubleNestedClass3 below) and also non public top level classes (PackagedTopLevelNonPublicTest) in addition to the traditional toplevel class tests (test4):

public class PackagedTopLevelTest {
  @Test
  public void test4() {
    System.out.println("Executed test.PackagedTopLevel#test4");
  }

  @Nested
  class NestedClass2 {
    @Test
    public void test6() {
      System.out.println("Executed test.PackagedTopLevelTest$NestedClass2#test6");
    }
    @Nested
    class DoubleNestedClass3 {
      @Test
      public void test8() {
        System.out.println("Executed test.PackagedTopLevelTest$NestedClass2$DoubleNestedClass3#test8");
      }
    }
  }

}

class PackagedTopLevelNonPublicTest {
    @Test
    public void test10() {
        System.out.println("Executed test.PackagedTopLevelNonPublic#test10");
    }
}

In addition to that Unittests can be placed in the default package and support the same set of special cases.

This PR adds support for these cases:

• running of single test from nested/top level non-public classes
• rerunning/debugging test from nested/top level non-public classes

In addition while investigating the fix, it was observed, that the unittest result extraction sometimes yielded an incomplete set. I.e. some of the test data was missing. Analysis showed, that he XML reports from maven surefire were not yet written/updated while the console output was already done.

Another identified problem fixed here was incomplete detection of Jupiter (JUnit5) usage in the unittest run.

It is inspired by the work from @ratcashdev.

Closes: #3975
Closes. #3995

[mbien]

javac.release=17

[matthiasblaesing]

Thanks - overlooked that. I would have sworn I had that corrected before, oh well 😄