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/CodeGen/link-bitcode-file.c b/clang/test/CodeGen/link-bitcode-file.c
index 7740406..7b2bfd6 100644
--- a/clang/test/CodeGen/link-bitcode-file.c
+++ b/clang/test/CodeGen/link-bitcode-file.c
@@ -1,6 +1,6 @@
 // RUN: %clang_cc1 -triple i386-pc-linux-gnu -DBITCODE -emit-llvm-bc -o %t.bc %s
 // RUN: %clang_cc1 -triple i386-pc-linux-gnu -mlink-bitcode-file %t.bc -O3 -emit-llvm -o - %s | FileCheck -check-prefix=CHECK-NO-BC %s
-// RUN: %clang_cc1 -triple i386-pc-linux-gnu -DBITCODE -mlink-bitcode-file %t.bc -O3 -emit-llvm -o - %s 2>&1 | FileCheck -check-prefix=CHECK-BC %s
+// RUN: not %clang_cc1 -triple i386-pc-linux-gnu -DBITCODE -mlink-bitcode-file %t.bc -O3 -emit-llvm -o - %s 2>&1 | FileCheck -check-prefix=CHECK-BC %s
 
 int f(void);