Run match filter loop in reverse order from the end of the path

Summary:
This doesn't change anything from the functionality POV, but will
hopefully enable us to merge the ExactMatch loop and also improve
sorting of OtherMatches in the future.

The benchmark does not show any noteworthy timing differences.

Subscribers: kdevelop-devel

Differential Revision: https://phabricator.kde.org/D11937