Fix instance method resolution with abstract accessors and methods

tests/language/abstract_method_test.dart

+// Copyright (c) 2014, 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";
+
+// Checks that abstract instance methods are correctly resolved.
+
+int get length => throw "error: top-level getter called";
+int set height(x) { throw "error: top-level setter called"; }
+width() { throw "error: top-level function called"; }
+
+class A {
+  int get length;     // Abstract instance getter.
+  int set height(x);  // Abstract instance setter.
+  int width();        // Abstract instance method.
+
+  // Must resolve to non-abstract length getter in subclass.
+  get useLength => length;
+  // Must resolve to non-abstract height setter in subclass.
+  setHeight(x) => height = x;
+  // Must resolve to non-abstract width() method in subclass.
+  useWidth() => width();
+}
+
+class A1 extends A {
+  int length;  // Implies a length getter.
+  int height;  // Implies a height setter.
+  int width() => 345;
+  A1(this.length);
+}
+
+main() {
+  var a = new A1(123);
+  Expect.equals(123, a.useLength);
+  a.setHeight(234);
+  Expect.equals(234, a.height);
+  Expect.equals(345, a.useWidth());
+  print([a.useLength, a.height, a.useWidth()]);
+}
+