8241770: Module xxxAnnotation() methods throw NCDFE if module-info.class found as resource in unnamed module

[Alan Bateman]

This is a bug in Module.getXXXAnnotation implementation where it 
accidentally locates a module-info.class on the class path (say if 
someone deploys a modular JAR on the class path). An oversight in the 
original implementation. Simple fix to override loadClass to do the 
right thing. I've kept the changes as minimal as possible as this is a 
change that may need to be back-ported. The webrev with the change and 
updated test is here:

http://cr.openjdk.java.net/~alanb/8241770/webrev/

Thanks,
Alan