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.

in other words, java.lang.invoke.MethodHandles.Lookup.

With the unit tests warnings were squashed by suppressing them with SuppressWarnings annotations, instead of
reparing the issues as was done with the source. Reasons being...
 * The tests might be relying on the types as they were defined.
 * If the tests were written to test against the correct forms they would've/should've stipulated those.
 * Even unused members might be important to tests so we attempt to change as little as possible.

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