Several mjsunit cleanups

test/mjsunit/harmony/regress/regress-4400.js

Index: test/mjsunit/harmony/regress/regress-4400.js
diff --git a/test/mjsunit/harmony/regress/regress-4400.js b/test/mjsunit/harmony/regress/regress-4400.js
deleted file mode 100644
index 7c42e4f557ad098c4778841285a7075498ba1bf7..0000000000000000000000000000000000000000
--- a/test/mjsunit/harmony/regress/regress-4400.js
+++ /dev/null
@@ -1,8 +0,0 @@
-// Copyright 2015 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Flags: --harmony-default-parameters --min-preparse-length=0
-
-function borked(a = [], b = {}, c) {}
-borked();