Review Request: 8104574 Update tests to prepare for system class loader not be URLClassLoader

[Mandy Chung]

http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8104574/webrev.00/

Pattern like this should be fixed as a ClassLoader is not necessary a 
URLClassLoader.  
   ((URLClassLoader) ThreadSafety.class.getClassLoader()

We have fixed several tests previously.  Two more are identified and fixed in 
this patch.

Mandy