Adding extra test info for llvm-mt.

llvm-svn: 308252
diff --git a/llvm/test/tools/llvm-mt/help.test b/llvm/test/tools/llvm-mt/help.test
index 8b8df06..20d1235 100644
--- a/llvm/test/tools/llvm-mt/help.test
+++ b/llvm/test/tools/llvm-mt/help.test
@@ -1,3 +1,5 @@
+RUN: not llvm-mt /hello /nonsense
+
 RUN: llvm-mt /? | FileCheck %s -check-prefix=HELP
 
 RUN: llvm-mt /inputresource:foo.res /manifest foo.manifest | FileCheck %s -check-prefix=NOT_SUPPORTED