Fix several bugs in closure conversion.

pkg/kernel/testcases/arity.dart

+/*

[Dmitry Stefantsov, 2017/08/24 09:41:13]

Please, use line comments for the preamble here and in other files.  See
https://www.dartlang.org/guides/language/effective-dart/documentation#dont-us....

[Dmitry Stefantsov, 2017/08/24 09:41:13]

I think this file belongs to `pkg/kernel/testcases/closures`.  Maybe, because
it's in the wrong directory, the corresponding `.expect` file wasn't generated.

[sjindel, 2017/08/24 11:11:43]

I think I just copied it from another file (maybe in co19?)

+ * Copyright (c) 2017, 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.
+ */
+main() {
+  var closures = [
+    (x, y, [z]) {},
+    (x, y, z) {},
+    (x, y, {z}) {},
+    (x, y, z, w, v) {}
+  ];
+  for (var c in closures) {
+    bool ok = false;
+    try {
+      c(1, 2, 3, 4);
+    } on NoSuchMethodError catch (_) {
+      ok = true;
+    }
+    if (!ok) {
+      throw new Exception("Expected an error!");
+    }
+  }
+}