Merging r167884,r167920 from trunk into 3.2 release branch

r167884

Don't try to save the assigned value in a Objective-C property assignment
if the type of the value is a non-trivial class type.  Fixes PR14318.

(There's a minor ObjC++ language change here: given that we can't save the
value, the type of the assignment expression is void in such cases.)

r167920

PR14279: Work around this major miscompilation by treating move operations as
non-trivial if they would not call a move operation, even if they would in fact
call a trivial copy operation. A proper fix is to follow, but this small
directed fix is intended for porting to the 3.2 release branch.

llvm-svn: 168324