Walker should check canonicalized type names

As we know, drgn type equality does not work right, so we need to
compare canonicalized type names.

When combined with openzfs/zfs#10236,
`zfs_dbgmsg` now works on ztest core dumps.

sdb/command.py

@@ -605,13 +605,13 @@ def _call(self, objs: Iterable[drgn.Object]) -> Iterable[drgn.Object]:
         the types as we go.
         """
         assert self.input_type is not None
-        type_ = target.get_type(self.input_type)
+        expected_type = type_canonicalize_name(self.input_type)
         for obj in objs:
-            if obj.type_ != type_:
+            if type_canonical_name(obj.type_) != expected_type:
                 raise CommandError(
                     self.name,
                     'expected input of type {}, but received {}'.format(
-                        type_, obj.type_))
+                        expected_type, type_canonical_name(obj.type_)))
 
             yield from self.walk(obj)