First step toward fixing <rdar://problem/6613046> refactor clang objc type representation.

Add a type (ObjCObjectPointerType) and remove a type (ObjCQualifiedIdType).

This large/tedious patch is just a first step. Next step is to remove ObjCQualifiedInterfaceType. After that, I will remove the magic TypedefType for 'id' (installed by Sema). This work will enable various simplifications throughout clang (when dealing with ObjC types). 

No functionality change.

llvm-svn: 73649
diff --git a/clang/lib/Analysis/RegionStore.cpp b/clang/lib/Analysis/RegionStore.cpp
index ee62d39..d67fa84 100644
--- a/clang/lib/Analysis/RegionStore.cpp
+++ b/clang/lib/Analysis/RegionStore.cpp
@@ -668,7 +668,7 @@
   QualType ToTy = Ctx.getCanonicalType(CastToTy);
 
   // Check cast to ObjCQualifiedID type.
-  if (isa<ObjCQualifiedIdType>(ToTy)) {
+  if (ToTy->isObjCQualifiedIdType()) {
     // FIXME: Record the type information aside.
     return CastResult(state, R);
   }