chore(ivy): add static flag to dialog-related static queries (#15239)

Author: kara

src/cdk-experimental/dialog/dialog-container.ts

@@ -97,7 +97,7 @@ export class CdkDialogContainer extends BasePortalOutlet implements OnDestroy {
   // tslint:disable:no-host-decorator-in-concrete
 
   /** The portal host inside of this container into which the dialog content will be loaded. */
-  @ViewChild(PortalHostDirective) _portalHost: PortalHostDirective;
+  @ViewChild(PortalHostDirective, {static: true}) _portalHost: PortalHostDirective;
 
   /** A subject emitting before the dialog enters the view. */
   _beforeEnter: Subject<void> = new Subject();

src/lib/dialog/dialog-container.ts

@@ -72,7 +72,7 @@ export function throwMatDialogContentAlreadyAttachedError() {
 })
 export class MatDialogContainer extends BasePortalOutlet {
   /** The portal outlet inside of this container into which the dialog content will be loaded. */
-  @ViewChild(CdkPortalOutlet) _portalOutlet: CdkPortalOutlet;
+  @ViewChild(CdkPortalOutlet, {static: true}) _portalOutlet: CdkPortalOutlet;
 
   /** The class that traps and manages focus within the dialog. */
   private _focusTrap: FocusTrap;

src/lib/snack-bar/snack-bar-container.ts

@@ -55,7 +55,7 @@ export class MatSnackBarContainer extends BasePortalOutlet implements OnDestroy
   private _destroyed = false;
 
   /** The portal outlet inside of this container into which the snack bar content will be loaded. */
-  @ViewChild(CdkPortalOutlet) _portalOutlet: CdkPortalOutlet;
+  @ViewChild(CdkPortalOutlet, {static: true}) _portalOutlet: CdkPortalOutlet;
 
   /** Subject for notifying that the snack bar has exited from view. */
   readonly _onExit: Subject<any> = new Subject();