menu: trigger ExpressionChangedAfterItHasBeenCheckedError aria-expanded: null in OnPush component

#### What is the expected behavior?
Error should not occur

#### What is the current behavior?
Repeatedly and quickly clicking on menu trigger button causes error

#### What are the steps to reproduce?
[StackBlitz](https://stackblitz.com/edit/angular-stgyux)
Click on menuTrigger repeatedly -> error shows in console

#### Which versions of Angular, Material, OS, TypeScript, browsers are affected?
Angular 7.1.0
Angular Material 7.1.0
Chrome Browser

#### Is there anything else we should know?
ChangeDetection: OnPush

ERROR
Error: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value: 'aria-expanded: true'. Current value: 'aria-expanded: null'.

Comienza con la reproducción vinculada de StackBlitz usando Angular y Angular Material 7.1.0; después, haz clic repetidamente en el activador del menú dentro de un componente OnPush mientras observas la consola. Rastrea los cambios de aria-expanded del activador del menú y determina por qué el valor comprobado cambia a null; se considera terminado cuando la reproducción ya no informa de ExpressionChangedAfterItHasBeenCheckedError.

Escrito por el modelo de indexación a partir del texto del issue.