Enhanced RC: Optimization of the initial collapsing
* mediawiki.special.changeslist.enhanced: Hide the rows that would be
hidden by jquery.makeCollapsible with CSS to save us some reflows
and repaints. This doesn't work on browsers that don't fully support
CSS2 (IE6), but it's okay, this will be done in JavaScript with old
degraded performance instead.
* jquery.makeCollapsible: Allow the element to be hidden on initial
toggle without removing and adding back the 'mw-collapsed' class.
This wasn't a performance issue in the past, but now it would
cause the newly added CSS rules to have to be recalculated (although
browsers seem to optimize it and avoid repaints at least).
Bug: 51749
Change-Id: I3823c2a67d524e6598e2437e1dd065659d1c7e41