Fold together the two implementations of 6.7.3p2 in SemaType. Fix two bugs, each of which was only present in one version:
 * Give the right diagnostic for 'restrict' applied to a non-pointer, non-reference type.
 * Don't reject 'restrict' applied indirectly to an Objective-C object pointer type (eg, through template instantiation).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178200 91177308-0d34-0410-b5e6-96231b3b80d8