Quick optimisation to avoid containsComparableForSerialization

As that method makes expensive ve.compare calls, we can quickly
avoid most cases by testing AnnotationSet#contains first.

On page load this reduces the number of ve.compare calls on
[[:en:Argentina]] from ~6,000,000 to about ~2,000.

Also reduces ve.compare calls per backspace keystroke from
~300 to 2.

We can optimise this further, but this is a good simple start.

Bug: 52013
Change-Id: Ie3b4517fd13383c48acb64b3c4e82051c34e7484
Merge "Quick optimisation to avoid containsComparableForSerialization"