Do not infer types of arguments of closures and methods named "call".

tests/language/call_argument_inference_test.dart

Index: tests/language/call_argument_inference_test.dart
===================================================================
--- tests/language/call_argument_inference_test.dart	(revision 0)
+++ tests/language/call_argument_inference_test.dart	(revision 0)
@@ -0,0 +1,14 @@
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import "package:expect/expect.dart";
+
+class A {
+  call(a) => a is num;
+}
+
+main() {
+  Expect.isTrue(new A().call(42));
+  Expect.isFalse(new A()('foo'));
+}