RFR(L): 8077838: Recent developments for ppc.

[Lindenmaier, Goetz]

Hi,

this change contains recent changes in the ppc directory mostly made by SAP.
It's a ppc-only change.
http://cr.openjdk.java.net/~goetz/webrevs/8077838-ppc/webrev.01/

 - Recognition of Power 8 processors (by Tiago Sturmer Daitx).
 - Support for more new Power 8 instructions.
 - Support for transactional memory. This is implemented but not yet tested
   thoroughly due to limitiations of the OS support. Not enabled.
 - java.lang.math.*Exact intrinsics
 - Some C2 optimizations and fixes:
   * Handling of flag registers. Some instructions would lead to uncompilable
     methods due to not allocatable register patterns.
   * Free some integer registers to use them for allocation. Handle compressed
     oops base as constant.
   * Unscaled class compression.
 - Type profiling fixes.

Please review this change.

Best regards,
  Goetz.