fix broken test

Author: mmalerba

src/material-experimental/mdc-list/list.spec.ts

@@ -1,3 +1,6 @@
+import {MatList} from '@angular/material-experimental/mdc-list';
+
 it('should have unit tests', () => {
   // TODO: Implement.
+  expect(MatList).toBe(MatList);
 });