Tweaks for review comments.

pkg/analysis_server/test/index/b_plus_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.
 
 library test.index.b_plus_tree;
 
 import 'dart:math';
 
 import 'package:analysis_server/src/index/b_plus_tree.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 624 matching lines @@
       expect(tree.find(i), isNull);
     }
   }
 
   void test_stress_random() {
     tree = _createTree(10, 10);
     int maxKey = 1000000;
     int tryCount = 1000;
     Set<int> keys = new Set<int>();
     {
-      Random random = new Random();
+      Random random = new Random(37);
       for (int i = 0; i < tryCount; i++) {
         int key = random.nextInt(maxKey);
         keys.add(key);
         _insert(key, 'V$key');
       }
     }
     // find every
     for (int key in keys) {
       expect(tree.find(key), 'V$key');
     }
     // remove random keys
     {
-      Random random = new Random();
+      Random random = new Random(37);
       for (int key in new Set<int>.from(keys)) {
         if (random.nextBool()) {
           keys.remove(key);
           expect(tree.remove(key), 'V$key');
         }
       }
     }
     // find every remaining key
     for (int key in keys) {
       expect(tree.find(key), 'V$key');
     }
   }
 
   void _insert(int key, String value) {
     tree.insert(key, value);
   }
 
   void _insertValues(int count) {
     for (int i = 0; i < count; i++) {
       _insert(i, 'V$i');
     }
   }
 }
 
 class _TestBTree<K, V> extends BPlusTree<K, V, int> {
   _TestBTree(int maxIndexKeys, int maxLeafKeys, Comparator<K> comparator) :
       super(comparator, new MemoryNodeManager(maxIndexKeys, maxLeafKeys));
 }