Set ordinals of all File's created in MachO passes.

Set ordinals of all File's created in MachO passes.

When we do debug printing of atoms, they expect their parent file
to have an ordinal.  Right now we trigger a bunch of asserts.

This doesn't actually manifest in differences in any real tests, but
even if the only thing it does is improve debuggability then its still
useful.

llvm-svn: 259450