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

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

llvm-svn: 185652
diff --git a/clang/test/CodeGenCXX/cxx11-exception-spec.cpp b/clang/test/CodeGenCXX/cxx11-exception-spec.cpp
index 49ca861..96ea1d7 100644
--- a/clang/test/CodeGenCXX/cxx11-exception-spec.cpp
+++ b/clang/test/CodeGenCXX/cxx11-exception-spec.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -std=c++11 -emit-llvm %s -o - -verify -fexceptions -fcxx-exceptions -triple x86_64-linux-gnu | FileCheck %s
+// RUN: not %clang_cc1 -std=c++11 -emit-llvm %s -o - -verify -fexceptions -fcxx-exceptions -triple x86_64-linux-gnu | FileCheck %s
 
 void h();