Attempting to fix XHR tests again.

tests/html/xhr_test.dart

Index: tests/html/xhr_test.dart
diff --git a/tests/html/xhr_test.dart b/tests/html/xhr_test.dart
index a7036e6e6077bc133635a281ba46b18240431b86..8ddae007792bc1b9857ea311bda4c529ec938d0a 100644
--- a/tests/html/xhr_test.dart
+++ b/tests/html/xhr_test.dart
@@ -193,7 +193,7 @@ main() {
 
         // 10MB of payload data w/ a bit of data to make sure it
         // doesn't get compressed to nil.
-        var data = new Uint8List(10 * 1024 * 1024);
+        var data = new Uint8List(1 * 1024 * 1024);
         for (var i = 0; i < data.length; ++i) {
           data[i] = i & 0xFF;
         }