[red-knot] Don't use separate ID types for each alist (#16415)

Regardless of whether #16408 and #16311 pan out, this part is worth
pulling out as a separate PR.

Before, you had to define a new `IndexVec` index type for each type of
association list you wanted to create. Now there's a single index type
that's internal to the alist implementation, and you use `List<K, V>` to
store a handle to a particular list.

This also adds some property tests for the alist implementation.

Author: dcreager

.github/workflows/daily_property_tests.yaml

@@ -47,6 +47,7 @@ jobs:
         run: |
           export QUICKCHECK_TESTS=100000
           for _ in {1..5}; do
+            cargo test --locked --release --package red_knot_python_semantic -- --ignored list::property_tests
             cargo test --locked --release --package red_knot_python_semantic -- --ignored types::property_tests::stable
           done
 

crates/red_knot_python_semantic/src/lib.rs

@@ -14,6 +14,7 @@ pub use semantic_model::{HasType, SemanticModel};
 pub mod ast_node_ref;
 mod db;
 pub mod lint;
+pub(crate) mod list;
 mod module_name;
 mod module_resolver;
 mod node_key;