RFR (L, final): 8218626: Add detailed message to NullPointerException describing what is null.

[Schmelter, Ralf]

Hi Goetz,

just one thing:
 
>> In NullPointerExceptionTest.java:
> > 
> > It seems you don't have tests for invokeinterface or invokespecial calls to cause
> > an NPE (e.g. by calling a null interface variable or a private non-static method
> > of a null objects).
> That is because the code is the same as for invokevirtual in all places in 
> bytecodeUtils.cpp.

The test should not omit these two bytecodes because the current implementation is the same. This can change and it is not much additional code to add the two cases.

Thanks and best regards,
  Goetz.