Only pass -coverage-notes-file when emitting coverage

The only functional change here is that -coverage-notes-file is not
passed to -cc1 in some situations.

This code appears to be trying to put the gcno and gcda output next to
the final object file, but it's doing that in a really convoluted way
that needs to be re-examined. It looks for -c or -S in the original
command, and then looks at the -o argument if present in order to handle
the -fno-integrated-as case. However, this doesn't work if this is a
link command with multiple inputs. I looked into fixing this, but the
check-profile test suite has a lot of dependencies on this behavior, so
I left it all alone.

llvm-svn: 373004