9003176: Class reference duplicates in constant pool

[Nándor Krácser]

Hi Compiler-Group,

for this harmless bug described in the subject I did a very simple patch. When a StacMapTable is being built the compiler adds some new entries (ClassType) to the constant Pool but these classes are often already there in the Pool but identified by ClassSymbols.

The patch: https://gist.github.com/bonifaido/5644680

Please verify this patch and help me improve it (how should I extends the test suite to test this?)

Regards,
Nandor