fix: defer handles of async functions

src/java/me/topchetoeu/jscript/lib/AsyncFunctionLib.java

@@ -54,7 +54,7 @@ public class AsyncFunctionLib extends FunctionValue {
                     public void onReject(EngineException err) {
                         next(ctx, Values.NO_RETURN, err);
                     }
-                });
+                }.defer(ctx));
             }
         }
 

src/java/me/topchetoeu/jscript/lib/AsyncGeneratorLib.java

@@ -62,7 +62,7 @@ public class AsyncGeneratorLib {
                 @Override public void onReject(EngineException err) {
                     next(ctx, Values.NO_RETURN, Values.NO_RETURN, err);
                 }
-            });
+            }.defer(ctx));
         }
         else if (state == 2) {
             var obj = new ObjectValue();