Revert "Build Observatory with runtime"

runtime/observatory/test/dominator_tree_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:observatory/dominator_tree.dart';
-import 'package:unittest/unittest.dart';
-
-void main() {
-  test('small example from [Lenguaer & Tarjan 1979]', smallTest);
-  test('non-flowgraph', nonFlowgraph);
-}
-
-void smallTest() {
-  var g = {
-    'R': ['A', 'B', 'C'],
-    'A': ['D'],
-    'B': ['A', 'D', 'E'],
-    'C': ['F', 'G'],
-    'D': ['L'],
-    'E': ['H'],
-    'F': ['I'],
-    'G': ['I', 'J'],
-    'H': ['E', 'K'],
-    'I': ['K'],
-    'J': ['I'],
-    'K': ['I', 'R'],
-    'L': ['H'],
-  };
-  var d = new Dominator();
-  for (String u in g.keys) {
-    d.addEdges(u, g[u]);
-  }
-  d.computeDominatorTree('R');
-  expect(d.dominator('I'), equals('R'));
-  expect(d.dominator('K'), equals('R'));
-  expect(d.dominator('C'), equals('R'));
-  expect(d.dominator('H'), equals('R'));
-  expect(d.dominator('E'), equals('R'));
-  expect(d.dominator('A'), equals('R'));
-  expect(d.dominator('D'), equals('R'));
-  expect(d.dominator('B'), equals('R'));
-  
-  expect(d.dominator('F'), equals('C'));
-  expect(d.dominator('G'), equals('C'));
-  expect(d.dominator('J'), equals('G'));
-  expect(d.dominator('L'), equals('D'));
-  expect(d.dominator('R'), isNull);
-}
-
-void nonFlowgraph() {
-  var d = new Dominator();
-  d.addEdges('A', ['B']);
-  expect(() => d.computeDominatorTree('B'), throwsStateError);
-}