dirstate._normalize: don't construct dirfoldmap if not necessary Constructing the dirfoldmap is expensive, so if there's a hit in the filefoldmap, don't construct the directory foldmap. This helps with cases like 'hg add foo' where foo is already tracked: for a large repository, the operation goes from 1.5 seconds to 1.2 (which is still way too much, but that's a matter for another day.)