RFR: 8205607: Use oop_iterate instead of oop_iterate_no_header

[Stefan Karlsson]

Hi all,

Please review this patch to use oop_iterate instead of 
oop_iterate_no_headers.

http://cr.openjdk.java.net/~stefank/8205607/webrev.01/
https://bugs.openjdk.java.net/browse/JDK-8205607

oop_iterate_no_header is a convenience function that allows developers 
to pass in sub classes of OopClosures, instead of sub classes of 
OopIterateClosure, to the oop_iterate machinery.

I propose that we remove this function, and change the few closures 
where this is used, to inherit from OopIterateClosure instead of OopClosure.

Thanks,
StefanK