RFR (S): 8162104: Use in_cset() instead of obj_in_cs()

[Thomas Schatzl]

Hi all,

  could I have reviews for this small cleanup that removes the use of
an obsolete method?

G1CollectedHeap::obj_in_cs() provides the same functionality as
G1CollectedHeap::is_in_cset(), except being slower. In fact, we had
asserts in the is_in_cset() code that used obj_in_cs.

Obj_in_cs has only been used in asserts too.

I see no need to maintain two versions of the same thing, hence the
removal.

CR:
https://bugs.openjdk.java.net/browse/JDK-8162104
Webrev:
http://cr.openjdk.java.net/~tschatzl/8162104/webrev/
Testing:
jprt

Thanks,
  Thomas