Big merge from experimental to bleeding edge.

tests/language/double_to_string_as_fixed2_test.dart

+// Copyright (c) 2012, 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.
+// Test basic integer operations.
+
+main() {
+  Expect.throws(() => 0.0.toStringAsFixed(-1),
+                (e) => e is RangeError);
+  Expect.throws(() => 0.0.toStringAsFixed(21),
+                (e) => e is RangeError);
+  Expect.throws(() => 0.0.toStringAsFixed(null),
+                (e) => e is ArgumentError);
+  Expect.throws(() => 0.0.toStringAsFixed(1.5),
+                (e) => e is ArgumentError || e is TypeError);
+  Expect.throws(() => 0.0.toStringAsFixed("string"),
+                (e) => e is ArgumentError || e is TypeError);
+  Expect.throws(() => 0.0.toStringAsFixed("3"),
+                (e) => e is ArgumentError || e is TypeError);
+}