Tweak CGU sorting in a couple of places.
In `base.rs`, tweak how the CGU size interleaving works. Since #113777, it's much more common to have multiple CGUs with identical sizes. With the existing code these same-sized items ended up in the opposite-to-desired order due to the stable sorting. The code now starts with a reverse sort (like is done in `partitioning.rs`) which gives the behaviour we want. This doesn't matter much for perf, but makes profiles in `samply` look more like what we expect.
In `partitioning.rs`, we can use `sort_by_key` instead of `sort_by_cached_key` because `CGU::size_estimate()` is cheap. (There is an identical CGU sort earlier in that function that already uses `sort_by_key`.)
r? `@pnkfelix`
Matthias Krüger
c3cd05198a