No functionality change. Rename emitGCNO() to the more sensible
emitProfileNotes(), similar to emitProfileArcs(). Also update its comment.

Also add a comment on Version[4] (there will be another comment in clang later),
and compress lines that exceeded 80 columns.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176994 91177308-0d34-0410-b5e6-96231b3b80d8