Bug 1525129 - Fix intermittent in browser_webconsole_reverse_search_mouse_navigation.js; r=Honza.

Based on the failure logs, it looks like the test fails because
a node highlighter is being triggered while the toolbox is
closed.
Changing one of the input to not display any nodes in the output
should fix the issue.

Differential Revision: https://phabricator.services.mozilla.com/D19341

--HG--
extra : moz-landing-system : lando

devtools/client/webconsole/test/mochitest/browser_webconsole_reverse_search_mouse_navigation.js

@@ -14,7 +14,7 @@ add_task(async function() {
   const jstermHistory = [
     `document`,
     `document
-       .querySelectorAll("*")
+       .querySelectorAll("span")
        .forEach(console.log)`,
     `Dog = "Snoopy"`,
   ];