Prior to this change, the INSTANCE constant one could refer to on
AnnotationAwareOrderComparator actually referred to the constant
declared in the OrderAwareComparator superclass. Thus
AnnotationAwareOrderComparator#INSTANCE did not actually return an
AnnotationAwareOrderComparator but an OrderAwareComparator instead. This
commit introduces a dedicated constant on AnnotationAwareOrderComparator
to avoid this glitch.
Issue: SPR-10038
e40e2b7cae