test(sidenav): fix sidenav failures under Ivy (#15300)

* Fixes one unit test that was depending on static queries.
* Fixes the remaining 16 failures that were due to some code that was commented out while waiting for a task which was resolved.

Author: crisbeto

src/lib/sidenav/drawer.spec.ts

@@ -699,6 +699,7 @@ describe('MatDrawerContainer', () => {
     it('should be able to explicitly enable the backdrop in `side` mode', fakeAsync(() => {
       const fixture = TestBed.createComponent(BasicTestApp);
       const root = fixture.nativeElement;
+      fixture.detectChanges();
 
       fixture.componentInstance.drawer.mode = 'side';
       fixture.detectChanges();