Fix "**" precedence in AntPathMatcher comparator

Prior to this commit, "{" and "*" chars in patterns had equal
weight when comparing patterns. So when comparing several
patterns, the computed order was:
1- /hotels/{hotel}/bookings/{booking}
2- /hotels/**
3- /hotels/{hotel}/bookings/{booking}/customer/{customer}

This commit updates the comparator so that "**"
(matches zero or more 'directories' in a path) are now counted
separately.
The pattern with less "**" now takes precedence.

Issue: SPR-6741