fix(material/select): run viewportRuler change event outside the zone

MatSelect component was listening viewportRuler change event inside the zone. Due to this, a CD cycle was fired after every 'resize' event, event there was nothing to detect changes. It only make sense to run a CD cycle if the mat-select panel is open.

Fixes #18546

Author: llorenspujol

src/material/select/select.ts

@@ -568,14 +568,18 @@ export class MatSelect extends _MatSelectMixinBase implements AfterContentInit,
         }
       });
 
-    this._viewportRuler.change()
-      .pipe(takeUntil(this._destroy))
-      .subscribe(() => {
-        if (this._panelOpen) {
-          this._triggerRect = this.trigger.nativeElement.getBoundingClientRect();
-          this._changeDetectorRef.markForCheck();
-        }
-      });
+    this._ngZone.runOutsideAngular(() => 
+      this._viewportRuler.change()
+        .pipe(takeUntil(this._destroy))
+        .subscribe(() => {
+          if (this._panelOpen) {
+            this._ngZone.run(() => {
+              this._triggerRect = this.trigger.nativeElement.getBoundingClientRect();
+              this._changeDetectorRef.markForCheck();
+            })
+          }
+        })
+    );
   }
 
   ngAfterContentInit() {