Fix the case when a reference to an address taken BB is emitted in one

Fix the case when a reference to an address taken BB is emitted in one
function, then the BB is RAUW'd before the definition is emitted.  There
are still two cases not being handled, but this should improve us back to
the situation before I touched anything.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98566 91177308-0d34-0410-b5e6-96231b3b80d8