InstrProf: Set profile data to visibility hidden

Shared objects are fairly broken for InstrProf right now -- a follow-up
commit in compiler-rt will fix the rest of this.

The main problem here is that at link time, profile data symbols in the
shared object might get used instead of symbols from the main
executable, creating invalid profile data sections.

<rdar://problem/16918688>

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@208939 91177308-0d34-0410-b5e6-96231b3b80d8
Switch another write_escaped to yaml::escape

I missed one in r206443.

git-svn-id: http://llvm.org/svn/llvm-project/cfe/trunk@208941 91177308-0d34-0410-b5e6-96231b3b80d8