Don't leave an output file in the test directory.

llvm-svn: 56910
diff --git a/llvm/test/Assembler/2008-09-02-FunctionNotes2.ll b/llvm/test/Assembler/2008-09-02-FunctionNotes2.ll
index 6a5116b..966e0f8 100644
--- a/llvm/test/Assembler/2008-09-02-FunctionNotes2.ll
+++ b/llvm/test/Assembler/2008-09-02-FunctionNotes2.ll
@@ -1,5 +1,5 @@
 ; Test function notes
-; RUN: not llvm-as  %s |& grep "only one inline note" 
+; RUN: not llvm-as %s -o /dev/null -f |& grep "only one inline note" 
 ; XFAIL: *
 define void @fn1() alwaysinline  noinline {
   ret void