Objective-C [IRGen]. Fixes a crash in IRGen involving use of
'typeof' to extract type of an @encode expression used
in an initializer. // rdar://16655340


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@207004 91177308-0d34-0410-b5e6-96231b3b80d8