Make tests wait until automation is done to prevent leaks

third_party/WebKit/LayoutTests/imported/wpt_automation/pointerevents/pointerevent_pointerout-manual-automation.js

 importAutomationScript('/pointerevents/pointerevent_common_input.js');
 
 function inject_input() {
-  mouseMoveIntoTarget('target0');
-  mouseMoveToDocument();
+  return mouseMoveIntoTarget('target0').then(function() {
+    mouseMoveToDocument();
+  });
 }