RFR (XS): 8196883: G1RemSet::refine_card_concurrently doesn't need to check for cards in collection set

[Thomas Schatzl]

Hi all,

  can I have reviews for this small change that removes obsolete code
in concurrent refinement processing?

from the CR: "G1RemSet::refine_card_concurrently tests whether the
region is in the collection set, skipping refinement if so, with an
explanation that objects in the cset are about to move. But the cset is
a collection pause artifact, and is clear when not in a GC pause. The
test was useful when there was a single refine_card function that was
used both concurrently and during a GC pause, but JDK-8177707 split the
two cases into separate functions. It is no longer useful, and should
be removed."

CR:
https://bugs.openjdk.java.net/browse/JDK-8196883
Webrev:
http://cr.openjdk.java.net/~tschatzl/8196883/webrev/
Testing:
hs-tier 1-5

Thanks,
  Thomas