improve performance when scanning for quests

[Helium314]

OsmFilterQuestType quests always uses element tags, so there is no need to check whether an element without tags is applicable.
This change results in ~15-30% faster creation of quests in a bbox.

[westnordost]

I am surprised that this results in that much of a performance increase. After all, this should just be the reduction of iterations, since the ElementFilterExpression already skips elements without no tags if the expression allows it (see mayEvaluateToTrueWithNoTags). I guess, Kleinvieh macht auch Mist... with close to 100 filter quest types...

But anyway, from the technical point of view, the PR is kind of a hack. There is nothing inherent in OsmFilterQuestType that guarantees that there will never be a quest that also creates quests for elements with no tags.

However, this can be done in a less hacky way by making mayEvaluateToTrueWithNoTags public and then checking if(questType is OsmFilterQuestType && !questType.filter.mayEvaluateToTrueWithNoTags) doTheShortcut()

[westnordost]

see previous comment. Also, better add a short comment that explains what and why it is being done. I'd suggest to also rename elementsWithTags to onlyElementsWithTags

[westnordost]

👍 Nice find and implementation by the way! Such a performance gain for just 10 lines of code is pretty neat!