[red-knot] add call checking

[carljm]

Summary

This implements checking of calls.

I ended up following Micha's original suggestion from back when the signature representation was first introduced, and flattening it to a single array of parameters. This turned out to be easier to manage, because we can represent parameters using indices into that array, and represent the bound argument types as an array of the same length.

Starred and double-starred arguments are still TODO; these won't be very useful until we have generics.

The handling of diagnostics is just hacked into return_ty_result, which was already inconsistent about whether it emitted diagnostics or not; now it's even more inconsistent. This should probably be addressed somehow before this lands.

The new benchmark errors here surface the need for intersection support in is_assignable_to.

Fixes #14161.

Test Plan

Added mdtests.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.