KFilePlacesView: have setUrl() handle trailing slashes in place URLs
Whilst KFilePlacesView::setUrl() correctly strips its argument when comparing it to place URLs, it fails to strip the place URL itself. This means that if a place URL contains a trailing slash, it is not correctly highlighted in the place view.
Instead of comparing both QUrl objects directly, use QUrl::matches, which allows us to pass QUrl::StripTrailingSlash to both.
Add a test case for this behaviour as well.
Note: I have tested this successfully on 6.5.0. The patch applies cleanly to current master, but I don't have the 6.6.0 libraries set up to make absolutely sure it works.
This is also my first time working with a Qt codebase. I tried to make the test as succinct as possible, but please let me know if it needs any changes, major or minor.