Bug 1603222 - Enable geckodriver debug logging by default in CI for raptor-browsertime tests r=tarek,stephendonner

Differential Revision: https://phabricator.services.mozilla.com/D57559

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

testing/profiles/raptor/user.js

@@ -25,3 +25,6 @@ user_pref("toolkit.content-background-hang-monitor.disabled", true);
 // disable async stacks to match release builds
 // https://developer.mozilla.org/en-US/docs/Mozilla/Benchmarking#Async_Stacks
 user_pref('javascript.options.asyncstack', false);
+
+// enable marionette trace logging
+user_pref('marionette.log.level', 'Trace');