fixes #27586, prefer context type in generic inference

tests/lib_strong/html/documentfragment_test.dart

Index: tests/lib_strong/html/documentfragment_test.dart
diff --git a/tests/lib_strong/html/documentfragment_test.dart b/tests/lib_strong/html/documentfragment_test.dart
index 3b5249fba578243564eeef0804418774e3c14140..1f7a861de80f497534548467c9430dad4ffb8ee3 100644
--- a/tests/lib_strong/html/documentfragment_test.dart
+++ b/tests/lib_strong/html/documentfragment_test.dart
@@ -173,6 +173,7 @@ main() {
     var fragment = new DocumentFragment.html(
       "<div class='foo'><a>foo</a><b>bar</b></div>");
     expect(fragment.query(".foo a").tagName, "A");
-    expect(_nodeStrings(fragment.queryAll(".foo *")), equals(["A", "B"]));
+    expect(_nodeStrings(fragment.queryAll<Element>(".foo *")),
+        equals(["A", "B"]));
   });
 }