Fix branch reachabiliy annotation for temp dtor branches.

As we only create temp dtor decision branches when a temp dtor needs to
be run (as opposed to for each logical branch in the original
expression), we must include the information about all previous logical
branches when we annotate the temp dtor decision branch.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@215188 91177308-0d34-0410-b5e6-96231b3b80d8