Use suite events for more accurate reporting

[marcphilipp]

In 4.13 testSuiteStarted/Finished were introduced. While top-level test
class events were already reported at the appropriate time, events for
intermediate levels such as iterations of the Parameterized runner or
classes executed by the Suite runner were created synthetically when
the first test was started and the last test was finished, respectively.

---

I hereby agree to the terms of the JUnit Contributor License Agreement.

---

Definition of Done

• There are no TODOs left in the code
• Method preconditions are checked and documented in the method's Javadoc
• Coding conventions (e.g. for logging) have been followed
• Change is covered by automated tests including corner cases, errors, and exception handling
• Public API has Javadoc and @API annotations
• Change is documented in the User Guide and Release Notes
• All continuous integration builds pass