Don't run internalize if we're outputing bit-code and not an object file.

The problem with running internalize before we're ready to output an object file
is that it may change a 'weak' symbol into an internal one, but that symbol
could be needed by an external object file --- e.g. with arclite.

<rdar://problem/14334895>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185882 91177308-0d34-0410-b5e6-96231b3b80d8