Convert quality tests in main methods into JUnit tests

[TilmanNeumann]

The jml library has many classes where quality assurance tests are done in main methods. These should be converted into JUnit tests, for CI and anyway.

If the runtime of such a test is very long (like >10 seconds, minutes, hours), the test might be split into a fast JUnit test and a slow manual test.

[TilmanNeumann]

Mission accomplished. All main() method have either been converted into unit tests or renamed into something like *PerformanceTest or *Runner. The only class with main() method remaining in the main scope is CombinedFactorAlgorithmRunner, which is the execution target of the executable jar.

There is now a basic stock of 265 unit tests. Test coverage could be better but that will come little by little.