An element restricting a base model group is treated as a synthetic group with
minOccurs=maxOccurs=1 holding the element (XSD 1.0 sec 3.9.6), so its {1,1}
occurrence must be within the base group's range: a base group that must occur
two or more times cannot be restricted to a single element. The element's own
occurrence is still matched against the base branch it maps to, so an optional
element restricting a once-or-more base group stays valid.
XSTS invalid-schemas-accepted 181 to 179, no other bucket moved.
Mihaela Mihaljevic
c3876a261f