fix promise to be async.

Runtime/promise/Promise.cs

                 Promise.PendingPromises.Remove(this);
             }
 
-            InvokeRejectHandlers(ex);
+            Window.instance.scheduleMicrotask(() => {
+                InvokeRejectHandlers(ex);
+            });
         }
 
         /// <summary>
                 Promise.PendingPromises.Remove(this);
             }
 
-            InvokeResolveHandlers(value);
+            Window.instance.scheduleMicrotask(() => {
+                InvokeResolveHandlers(value);
+            });
         }
 
         /// <summary>

Runtime/promise/Promise_NonGeneric.cs

                 PendingPromises.Remove(this);
             }
 
-            InvokeRejectHandlers(ex);
+            Window.instance.scheduleMicrotask(() => {
+                InvokeRejectHandlers(ex);
+            });
         }
 
 
                 PendingPromises.Remove(this);
             }
 
-            InvokeResolveHandlers();                
+            Window.instance.scheduleMicrotask(() => {
+                InvokeResolveHandlers();
+            });
         }