Add missing coverage for generics properties of dynamic and void. Fix reflectType(dynamic) in dart2…

tests/compiler/dart2js/mirrors_used_test.dart

Index: tests/compiler/dart2js/mirrors_used_test.dart
diff --git a/tests/compiler/dart2js/mirrors_used_test.dart b/tests/compiler/dart2js/mirrors_used_test.dart
index 27e412d874f1554b9724e880fc87146d5232252a..0099dc95d79701dc91ca5fdc091cef4f6e715ad0 100644
--- a/tests/compiler/dart2js/mirrors_used_test.dart
+++ b/tests/compiler/dart2js/mirrors_used_test.dart
@@ -58,7 +58,7 @@ void main() {
     // 2. Some code was refactored, and there are more methods.
     // Either situation could be problematic, but in situation 2, it is often
     // acceptable to increase [expectedMethodCount] a little.
-    int expectedMethodCount = 337;
+    int expectedMethodCount = 341;
     Expect.isTrue(
         generatedCode.length <= expectedMethodCount,
         'Too many compiled methods: '