Port Compositor::windowRepaintsPending to use std::any_of

Summary:
While investigating a repaint issue I had a hard time to work with the
code and decided to change it to a more modern variant.

Instead of duplicating the same logic for each of the lists it's now
moved into a dedicated templated method which used std::any_of. Which is
exactly the algorithm we need: if there is any window with a non empty
repaints region it should return true.

Reviewers: #kwin, #plasma

Subscribers: plasma-devel, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D3397