Workarond for Sauce Labs Android driver bug

"Selenium_user" for some reason becomes "SELENIUM_user", but only on
Sauce Labs+Android. Works just fine for other browsers and on a local
Android driver.

I have reported the bug to Sauce Labs and they are working on it.

Bug: 46223
Change-Id: I99f51f63b248c9fef739b0ff47a6ecf8e2009acb