Tweak reflective_tests _invokeSymbolIfExists to not swallow exceptions

pkg/analyzer/test/reflective_tests.dart

Index: pkg/analyzer/test/reflective_tests.dart
diff --git a/pkg/analyzer/test/reflective_tests.dart b/pkg/analyzer/test/reflective_tests.dart
index 24c36cb4fbd419dd8fc03faff9452b419c0ab28a..970743db783445e30337dedb20d0db4b9908955f 100644
--- a/pkg/analyzer/test/reflective_tests.dart
+++ b/pkg/analyzer/test/reflective_tests.dart
@@ -73,14 +73,15 @@ void runReflectiveTests(Type type) {
 
 Future _invokeSymbolIfExists(InstanceMirror instanceMirror, Symbol symbol) {
   var invocationResult = null;
+  InstanceMirror closure;
   try {
-    invocationResult = instanceMirror.invoke(symbol, []).reflectee;
+    closure = instanceMirror.getField(symbol);

[Jennifer Messerly, 2016/01/19 23:53:54]

Basically, we get the tearoff:
https://api.dartlang.org/1.13.2/dart-mirrors/ObjectMirror/getField.html

   } on NoSuchMethodError {}
-  if (invocationResult is Future) {
-    return invocationResult;
-  } else {
-    return new Future.value(invocationResult);
+
+  if (closure is ClosureMirror) {
+    invocationResult = closure.apply([]).reflectee;
   }
+  return new Future.value(invocationResult);
 }
 
 /**