[compiler] Move generator optimization heuristics.

src/factory.cc

Index: src/factory.cc
diff --git a/src/factory.cc b/src/factory.cc
index cee362588050ce732da537a0bc6a0a60fb84fcf4..02eea6b2b37601ac0edf2b18706190a3c9f53f95 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -2085,12 +2085,6 @@ Handle<SharedFunctionInfo> Factory::NewSharedFunctionInfo(
   shared->set_num_literals(number_of_literals);
   if (IsGeneratorFunction(kind)) {
     shared->set_instance_class_name(isolate()->heap()->Generator_string());
-    shared->DisableOptimization(kGenerator);
-  }
-  if (IsAsyncFunction(kind)) {
-    // TODO(caitp): Enable optimization of async functions when they are enabled
-    // for generators functions.
-    shared->DisableOptimization(kGenerator);
   }
   return shared;
 }