In ARC mode, consider Objective-C lifetime types (object pointers and

In ARC mode, consider Objective-C lifetime types (object pointers and
block pointers) that don't have any qualification to be POD types. We
were previously considering them to be non-POD types, because this was
convenient in C++ for is_pod-like traits. However, we now end up
inferring lifetime in such cases (template arguments infer __strong),
so it is not necessary.

Moreover, we want rvalues of object type (which have their lifetime
stripped) to be PODs to allow, e.g., va_arg(arglist, id) to function
properly. Fixes <rdar://problem/9758798>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134993 91177308-0d34-0410-b5e6-96231b3b80d8