Reduce running time of priority queue test.

pkg/collection/test/priority_queue_test.dart

Index: pkg/collection/test/priority_queue_test.dart
diff --git a/pkg/collection/test/priority_queue_test.dart b/pkg/collection/test/priority_queue_test.dart
index 3d9c9fdb7959774da105125b1eda0582c5b80fad..1040e1a021ddfdb09b31817b0a3afc824bab4c73 100644
--- a/pkg/collection/test/priority_queue_test.dart
+++ b/pkg/collection/test/priority_queue_test.dart
@@ -14,7 +14,7 @@ void main() {
 }
 
 void testInt(PriorityQueue<int> create()) {
-  for (int count in [1, 5, 127, 128, 400]) {
+  for (int count in [1, 5, 127, 128]) {
     testQueue("int:$count",
               create,
               new List<int>.generate(count, (x) => x),
@@ -23,7 +23,7 @@ void testInt(PriorityQueue<int> create()) {
 }
 
 void testCustom(PriorityQueue<C> create(comparator)) {
-  for (int count in [1, 5, 127, 128, 400]) {
+  for (int count in [1, 5, 127, 128]) {
     testQueue("Custom:$count/null",
               () => create(null),
               new List<C>.generate(count, (x) => new C(x)),