Remove implementations of mirror methods not in the API from the VM. Update tests.

tests/lib/mirrors/method_mirror_returntype_test.dart

Index: tests/lib/mirrors/method_mirror_returntype_test.dart
diff --git a/tests/lib/mirrors/method_mirror_returntype_test.dart b/tests/lib/mirrors/method_mirror_returntype_test.dart
index be551562dce72b79c37e64386884e712b1e34713..42ccda287ff985cc593a7c66fa8e1f6042b3bd1d 100644
--- a/tests/lib/mirrors/method_mirror_returntype_test.dart
+++ b/tests/lib/mirrors/method_mirror_returntype_test.dart
@@ -39,7 +39,7 @@ main() {
   Expect.equals(const Symbol("void"), mm.returnType.simpleName);
 
   ClassMirror cm = reflectClass(C);
-  mm = cm.members[#getE];
+  mm = cm.declarations[#getE];
   Expect.equals(true, mm.returnType is TypeMirror);
   // The spec for this is ambigious and needs to be updated before it is clear
   // what has to be returned.