* Speed up galley cache by only using the hash as key
This hashes the job but doesn't compare them with Eq,
which speeds up demo_with_tessellate__realistic by 5-6%,
winning back all the performance lost in
https://github.com/emilk/egui/pull/682
* Remove custom Eq/PartialEq code for LayoutJob and friends
* Silence clippy
* Unrelated clippy fixes