Skip correction for the under/overhang for non-italic fonts: it seems to
be pretty small for them and avoiding the calls to ::GetCharABCWidths()
makes GetTextExtent() 7-8 times faster, which seems to be a worthwhile
compensation.
If we decide to restore these calls in the future, we will need to
implement some kind of cache for them, as they're just too slow
otherwise.
70768a33d2