RFR: 8201209: Separate out CMS specific functions into CMSCardTable

[Stefan Karlsson]

Hi all,

Please review this patch to move CMS specific CardTableRS code into a 
new CMSCardTable class.

  http://cr.openjdk.java.net/~stefank/8201209/webrev.01/
  https://bugs.openjdk.java.net/browse/JDK-8201209

Erik Ö suggested that I named the class CMSCardTable instead of 
CMSCardTableRS, because CardTableRS would probably renamed in the future.

This patch makes it easier to conditionally compile out CMS in:
  https://bugs.openjdk.java.net/browse/JDK-8200729 - Conditional 
compilation of GCs

Thanks,
StefanK