Exceptional parallel execution on @NotThreadSafe type.

We want to execute tests in parallel.
 In some cases some tests want to be executed in a single Thread instance.
 For instance I am using Embedded Container OpenEJB which is singleton, thus does not support parallelism.
 Other tests want to be executed in parallel anyway.
 This simple principle avoids parallel execution in an elegant way in src/test/java.
I will remove forkCount. I don't know why it's here.

Some time ago the build rarely failed because of prolonged delays in my tests. I am testing against time spent by JUnitCore and thus I need to have some guarantees that developers would not report against me that the build is unstable. Now I am testing on several computer platforms and the build is very stable like this.