Correct maven-compiler-plugin JDK version for IDEA import Compiler bytecode version.

Remove JvstTestRoot's constructor, otherwise IDEA cannot show Run icon aside testMethod.
Another way is adding suite() static method to those classes.

Now we can clone and open project with IDEA 2023.2. Debug single test case with IDEA is very useful.

There were minimal changes:
Some tests had their own runners these were discontinued as IDEs/maven run the tests anyway.
Removed the main methods for these.
2 tests were dependent on the running order so added the test sorter.

All tests succeed on junit 4 with legacy support.

git-svn-id: http://anonsvn.jboss.org/repos/javassist/trunk@589 30ef5769-5b8d-40dd-aea6-55b5d6557bb3