Most of these tests have been disabled for a long time; they run well
in the current test environment.
With the additional tests running, task times increase; I have added one
more test chunk for android mochitest-plain.
These tests were identified from a random sampling of mochitest manifests;
I intend to enable more mochitests in future patches.
Differential Revision: https://phabricator.services.mozilla.com/D48912
--HG--
extra : moz-landing-system : lando
