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/Tooling/auto-detect-from-source-parent.cpp b/test/Tooling/auto-detect-from-source-parent.cpp
index f1dbc0f..5f27d5a 100644
--- a/test/Tooling/auto-detect-from-source-parent.cpp
+++ b/test/Tooling/auto-detect-from-source-parent.cpp
@@ -2,7 +2,7 @@
 // RUN: mkdir -p %t/abc/def/ijk/qwe
 // RUN: echo "[{\"directory\":\".\",\"command\":\"clang++ -c %t/abc/def/ijk/qwe/test.cpp\",\"file\":\"%t/abc/def/ijk/qwe/test.cpp\"}]" | sed -e 's/\\/\\\\/g' > %t/compile_commands.json
 // RUN: cp "%s" "%t/abc/def/ijk/qwe/test.cpp"
-// RUN: clang-check "%t/abc/def/ijk/qwe/test.cpp" 2>&1 | FileCheck %s
+// RUN: not clang-check "%t/abc/def/ijk/qwe/test.cpp" 2>&1 | FileCheck %s
 
 // CHECK: C++ requires
 invalid;