[red-knot] add call checking (#15200)

## 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 needs to be addressed, but
could be a follow-up.

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

Fixes #14161.

## Test Plan

Added mdtests.

crates/red_knot_python_semantic/resources/mdtest/assignment/augmented.md

@@ -40,9 +40,9 @@ class C:
         return 42
 
 x = C()
+# error: [invalid-argument-type]
 x -= 1
 
-# TODO: should error, once operand type check is implemented
 reveal_type(x)  # revealed: int
 ```