[F&O] 5.1 Constructor Functions for XML Schema Built-in Types

The result types for these constructor functions:

xs:dateTime($arg  as xdt:anyAtomicType) as (xs:dateTime, 
xdt:dayTimeDuration)
xs:time($arg as xdt:anyAtomicType) as (xs:time, xdt:dayTimeDuration)
xs:date($arg as xdt:anyAtomicType) as (xs:date, xdt:dayTimeDuration)

are no SequenceTypes. This is inconsistent wrt function declarations in 
the query prolog.

Till Westmann