RFR: 8075247: Cleanup specialized_oop_closures.hpp

[Stefan Karlsson]

Hi,

Please review this patch to rename and simplify some macros in 
specialized_oop_closures.hpp and g1_specialized_oop_closures.hpp.

The patch contains the following changes:
1) The FURTHER_SPECIALIZED* macros are only used by G1, so they have 
been renamed into SPECIALIZED_*G1.
2) Removed some unnecessary #ifdefs. The compile will catch the error if 
we try to redefine the macro.
3) Gather all CMS specific macros inside a new 
SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_CMS macro.

http://cr.openjdk.java.net/~stefank/8075247/webrev.01
https://bugs.openjdk.java.net/browse/JDK-8075247

Thanks,
StefanK