Revert 146728 as it's causing failures on some of the external bots as well as

internal nightly testers.  Original commit message:

By popular demand, link up types by name if they are isomorphic and one is an
autorenamed version of the other.   This makes the IR easier to read, because
we don't end up with random renamed versions of the types after LTO'ing a large
app.

llvm-svn: 146838