Factor out throwing of argument error.

runtime/lib/array.cc

Index: runtime/lib/array.cc
===================================================================
--- runtime/lib/array.cc	(revision 28096)
+++ runtime/lib/array.cc	(working copy)
@@ -21,18 +21,14 @@
     const String& error = String::Handle(String::NewFormatted(
         "Length must be an integer in the range [0..%" Pd "].",
         Array::kMaxElements));
-    const Array& args = Array::Handle(Array::New(1));
-    args.SetAt(0, error);
-    Exceptions::ThrowByType(Exceptions::kArgument, args);
+    Exceptions::ThrowArgumentError(error);
   }
   intptr_t len = Smi::Cast(length).Value();
   if (len < 0 || len > Array::kMaxElements) {
     const String& error = String::Handle(String::NewFormatted(
         "Length (%" Pd ") must be an integer in the range [0..%" Pd "].",
         len, Array::kMaxElements));
-    const Array& args = Array::Handle(Array::New(1));
-    args.SetAt(0, error);
-    Exceptions::ThrowByType(Exceptions::kArgument, args);
+    Exceptions::ThrowArgumentError(error);
   }
   const Array& new_array = Array::Handle(Array::New(len));
   new_array.SetTypeArguments(type_arguments);