RFR: 8212595: Remove unused size_helper() in oop_oop_iterate* in instanceKlass.inline.hpp

[Leo Korinth]

Hi!

This is a small clean-up.

I am removing calls to size_helper() in instanceKlass.inline.hpp. The 
size is never used, and the corresponding methods outside InstanceKlass 
already returns void instead of int.

Fast disassembly inspection of the oop_oop_iterate_reverse version 
reveals that the compiler output remains the same. That is, the compiler 
already understood that the code was unused. No performance improvement 
thus. The code becomes a bit simpler and corresponds better to the 
methods in the other *Klass files.

Enhancement:
https://bugs.openjdk.java.net/browse/JDK-8212595

Webrev:
http://cr.openjdk.java.net/~lkorinth/8212595/00/

Testing:
- mach5 tier1-3

Thanks, Leo