Make gr-hovercard-run_test independent of `now` time

Release-Notes: skip
Google-Bug-Id: b/249007236
Change-Id: Ibb6073ba8c027c4ed26700a0918786a5b191795d
diff --git a/polygerrit-ui/app/elements/checks/gr-hovercard-run_test.ts b/polygerrit-ui/app/elements/checks/gr-hovercard-run_test.ts
index 61bb809..4ae2a46 100644
--- a/polygerrit-ui/app/elements/checks/gr-hovercard-run_test.ts
+++ b/polygerrit-ui/app/elements/checks/gr-hovercard-run_test.ts
@@ -15,6 +15,8 @@
   let element: GrHovercardRun;
 
   setup(async () => {
+    const fakeNow = new Date('Sep 26 2022 12:00:00');
+    sinon.useFakeTimers(fakeNow);
     element = await fixture<GrHovercardRun>(html`
       <gr-hovercard-run class="hovered"></gr-hovercard-run>
     `);