Enhance test to check on expected rewritten output.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@94368 91177308-0d34-0410-b5e6-96231b3b80d8

test/Rewriter/rewrite-typeof.mm

-// RUN: %clang_cc1 -x objective-c++ -fblocks -fms-extensions -rewrite-objc -o - %s
+// RUN: %clang_cc1 -x objective-c++ -fblocks -fms-extensions -rewrite-objc %s -o %t-rw.cpp
+// RUN: FileCheck -check-prefix LP --input-file=%t-rw.cpp %s
 
 extern "C" {
 extern "C" void *_Block_copy(const void *aBlock);
@@ -18,3 +19,5 @@ int main() {
     return 0;
 }
 
+// CHECK-LP: ((void (^)(void))_Block_copy((const void *)(b)))
+