In the next part, the patch generated by a script removes "-moz" prefix
to all multi-column properties.
However, some of the tests already have standard multi-column properties
specified. To avoid duplicating CSS multi-column rules in these
files (after applying the next part), I manually remove the prefixed
rules beforehand as many as possible.
Differential Revision: https://phabricator.services.mozilla.com/D44869
--HG--
extra : moz-landing-system : lando
