XCOMMONS-442: Upgrade to Selenium 2.40
* Fix the code that hides the Addon bar on Firefox.

(cherry picked from commit d038d25b82cb736f8a02f35d8b06f87f5a2658f3)
XCOMMONS-442: Upgrade to Selenium 2.40
* Fix failing functional tests.

(cherry picked from commit ce58b51bf8c00777fdcd7a19c90fa68cf04a5412)
XCOMMONS-442: Upgrade to Selenium 2.40
* Better way to scroll the page to the top.

(cherry picked from commit 0cd59ac4f1918cfdf93488be8b3c027ccaed529f)
[misc] Attempt to fix flickering tests in platform.