[PGO] Enable compression in pgo instrumentation

This reduces sizes of instrumented object files, final binaries,
process images, and raw profile data.

The format of the indexed profile data remain the same.

Differential Revision: http://reviews.llvm.org/D16388 
 





git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260117 91177308-0d34-0410-b5e6-96231b3b80d8
17 files changed