Drop ObjCIndirectCopyRestoreExprs during template instantiation.

It's a kind of implicit conversion, which we generally drop, but
more importantly it's got very specific placement requirements.

rdar://13617051

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179254 91177308-0d34-0410-b5e6-96231b3b80d8