Remove special-case for arguments.toString to match ES5

test/mjsunit/regress/regress-124.js

Index: test/mjsunit/regress/regress-124.js
diff --git a/test/mjsunit/regress/regress-124.js b/test/mjsunit/regress/regress-124.js
index 81526b0eddb8705e48fb405c14d4e390931c056e..0b3aae5358605c14156e20d4feee581d66d39fcd 100644
--- a/test/mjsunit/regress/regress-124.js
+++ b/test/mjsunit/regress/regress-124.js
@@ -48,9 +48,9 @@ function F(f) {
   assertEquals("[object global]", eval("f()"));
 
   // Receiver should be the arguments object here.
-  assertEquals("[object Object]", eval("arguments[0]()"));
+  assertEquals("[object Arguments]", eval("arguments[0]()"));
   with (arguments) {
-    assertEquals("[object Object]", toString());
+    assertEquals("[object Arguments]", toString());
   }
 }