Bug 1363508 - Part 4: Add a test case for testing pointer event spoofing when fingerprinting resistance is on r=arthuredelstein,masayuki

This patch add a mochitest which tests all pointer events to assure
touch and pen pointer events will be spoofed into mouse pointer events.
However, we are not able to test the suppressing of the non-primary
pointer events since we cannot generate a pointer event with isPrimary
as false so far.

Depends on D6005

Differential Revision: https://phabricator.services.mozilla.com/D6006

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