Prevent debounced call to page.show in tests

Change-Id: I058f025f69183da0ec7dfa7a92bfc2b9e7488ae7

polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.js

diff --git a/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.js b/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.js
index 1188534..c28679c 100644
--- a/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.js
+++ b/polygerrit-ui/app/elements/shared/gr-list-view/gr-list-view.js
@@ -41,6 +41,10 @@
       'previous-page': '_handlePreviousPage',
     },
 
+    detached() {
+      this.cancelDebouncer('reload');
+    },
+
     _filterChanged(filter) {
       this.debounce('reload', () => {
         if (filter) {