Remove the stack map registry.

This commit removes the stack map registry and instead uses the existing
information from the store's module registry to lookup stack maps.

A trait is now used to pass the lookup context to the runtime, implemented by
`Store` to do the lookup.

With this change, module registration in `Store` is now entirely limited to
inserting the module into the module registry.

crates/runtime/src/instance/allocator/pooling.rs

@@ -1370,7 +1370,7 @@ mod test {
                             host_state: Box::new(()),
                             interrupts: std::ptr::null(),
                             externref_activations_table: std::ptr::null_mut(),
-                            stack_map_registry: std::ptr::null_mut(),
+                            stack_map_lookup: None,
                         },
                     )
                     .expect("allocation should succeed"),
@@ -1394,7 +1394,7 @@ mod test {
                 host_state: Box::new(()),
                 interrupts: std::ptr::null(),
                 externref_activations_table: std::ptr::null_mut(),
-                stack_map_registry: std::ptr::null_mut(),
+                stack_map_lookup: None,
             },
         ) {
             Err(InstantiationError::Limit(3)) => {}