RFR (S): 8035815 Cache-align and pad the fast card cache

[Thomas Schatzl]

Hi all,

  can I have reviews for the following change, another break-out of the
8027295 change (will update its webrev soon).

Following Stefan K.'s suggestion, it makes the padding of the fast card
cache to avoid false sharing a separate changeset.

It adds a new class in padding.inline.hpp which performs allocation and
the padding of the data structure.

Webrev:
http://cr.openjdk.java.net/~tschatzl/8035815/webrev/

CR:
https://bugs.openjdk.java.net/browse/JDK-8035815

Testing:
jprt

Thanks,
  Thomas