The specialization logic has been refactored to include a call to
`rtl_lookup` for host functions. This allows the specializer to
recognize and optimize calls to built-in runtime functions by directly
returning their specialized values.
Additionally, the `_rtl_lookup` field in `Specializer` has been renamed
to `rtl_lookup` for clarity. The `visit_call` method has also been
renamed to `specialize_call_logic` to better reflect its purpose, and it
now correctly handles `TailCall` nodes by preserving them.
Michael Schimmel
b8390a3431