Migrate the language tests up to arithmetic_test.

tests/language/abstract_syntax_test.dart

Index: tests/language/abstract_syntax_test.dart
diff --git a/tests/language/abstract_syntax_test.dart b/tests/language/abstract_syntax_test.dart
deleted file mode 100644
index dda5c64985f50ac298b27753013eb27048cddd72..0000000000000000000000000000000000000000
--- a/tests/language/abstract_syntax_test.dart
+++ /dev/null
@@ -1,20 +0,0 @@
-// 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.
-
-import "package:expect/expect.dart";
-
-main() {
-  var b = new B();
-  Expect.equals(42, b.foo());
-}
-
-class A {
-  foo(); // //# 00: static type warning
-  static bar(); // //# 01: compile-time error
-}
-
-class B extends A {
-  foo() => 42;
-  bar() => 87;
-}