RFR (XS): 8198703: Missing #include "gc/shared/cardTableModRefBS.hpp" in graphKit.hpp

[Erik Österlund]

Hi,

Please review this trivial fix. There is a missing include in 
graphKit.hpp to cardTableModRefBS.hpp used to check if reduce initial 
card marks should be used or not.

My solution is to simply move the implementation to the cpp file 
instead. I think the fix is trivial enough to only require one review.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8198703

Webrev:
http://cr.openjdk.java.net/~eosterlund/8198703/webrev.00/

Thanks,
/Erik