Improve test verification from r209172

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209175 91177308-0d34-0410-b5e6-96231b3b80d8

test/ARCMT/GC-check-warn-nsalloc.m

-// RUN: %clang_cc1 -arcmt-check -no-ns-alloc-error -triple x86_64-apple-darwin10 -fobjc-gc-only %s | not grep warning
+// RUN: %clang_cc1 -arcmt-check -Werror -no-ns-alloc-error -triple x86_64-apple-darwin10 -fobjc-gc-only %s
 // RUN: %clang_cc1 -arcmt-check -Wno-error=arcmt-ns-alloc -triple x86_64-apple-darwin10 -fobjc-gc-only %s 2>&1 | grep 'warning: \[rewriter\] call returns pointer to GC managed memory'
-// RUN: %clang_cc1 -arcmt-check -no-ns-alloc-error -triple x86_64-apple-darwin10 -fobjc-gc-only -x objective-c++ %s | not grep warning
+// RUN: %clang_cc1 -arcmt-check -Werror -no-ns-alloc-error -triple x86_64-apple-darwin10 -fobjc-gc-only -x objective-c++ %s
 // TODO: Investigate VerifyDiagnosticConsumer failures on these tests when using -verify.
 // rdar://10532541