RFR (S): 8231117: Remove G1EvacuationRootClosures::raw_strong_oops()

[Thomas Schatzl]

Hi all,

   can I have reviews for this small cleanup that removes the use of 
G1EvacuationRootClosures::raw_strong_oops() as its implementation always 
corresponds to a call to G1EvacuationRootClosures::strong_oops()?

Also the comment referenced some non-existent flushing, which even more 
indicates that this is only some dead code.

CR:
https://bugs.openjdk.java.net/browse/JDK-8231117
Webrev:
http://cr.openjdk.java.net/~tschatzl/8231117/webrev
Testing:
hs-tier1-5

Thanks,
   Thomas