eliminate some random .ll file outputs


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63117 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/struct-comma.c b/test/CodeGen/struct-comma.c
index b53013f..2930529 100644
--- a/test/CodeGen/struct-comma.c
+++ b/test/CodeGen/struct-comma.c
@@ -1,4 +1,4 @@
-// RUN: clang %s -emit-llvm -o %t
+// RUN: clang %s -emit-llvm -o -
 
 struct S {int a, b;} x;
 void a(struct S* b) {*b = (r(), x);}