test/CodeGen/struct-matching-constraint.c: Fixup not to emit garbage to source tree.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@136333 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/struct-matching-constraint.c b/test/CodeGen/struct-matching-constraint.c
index 3690333..40c444f 100644
--- a/test/CodeGen/struct-matching-constraint.c
+++ b/test/CodeGen/struct-matching-constraint.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -S -emit-llvm -triple armv7a-apple-darwin %s
+// RUN: %clang_cc1 -S -emit-llvm -triple armv7a-apple-darwin %s -o /dev/null
 typedef unsigned short uint16_t;
 typedef __attribute__((neon_vector_type(8))) uint16_t uint16x8_t;