Add 'not' to commands that are expected to fail.

This is at least good documentation, but also opens the possibility of
using pipefail.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185652 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/warn-reinterpret-base-class.cpp b/test/SemaCXX/warn-reinterpret-base-class.cpp
index 67902f7..36b8fda 100644
--- a/test/SemaCXX/warn-reinterpret-base-class.cpp
+++ b/test/SemaCXX/warn-reinterpret-base-class.cpp
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify -Wreinterpret-base-class -Wno-unused-volatile-lvalue %s
-// RUN: %clang_cc1 -std=c++11 -fsyntax-only -fdiagnostics-parseable-fixits -Wreinterpret-base-class -Wno-unused-volatile-lvalue %s 2>&1 | FileCheck %s
+// RUN: not %clang_cc1 -std=c++11 -fsyntax-only -fdiagnostics-parseable-fixits -Wreinterpret-base-class -Wno-unused-volatile-lvalue %s 2>&1 | FileCheck %s
 
 // PR 13824
 class A {