Consolidate imports in test_resolvers.py

This does not need two separate `if TYPE_CHECKING` blocks, splitting
the imports across two sections.

tests/test_resolvers.py

@@ -1,10 +1,8 @@
 from __future__ import annotations
 
+from collections import namedtuple
 from typing import TYPE_CHECKING, Any, Iterator, Sequence, Tuple
 
-if TYPE_CHECKING:
- from typing import Iterable, Mapping
-
 import pytest
 from packaging.requirements import Requirement
 from packaging.version import Version
@@ -16,18 +14,17 @@
  ResolutionImpossible,
  Resolver,
 )
+from resolvelib.resolvers import Resolution
 
 if TYPE_CHECKING:
+ from typing import Iterable, Mapping
+
  from resolvelib.resolvers import (
  Criterion,
  RequirementInformation,
  RequirementsConflicted,
  )
 
-from collections import namedtuple
-
-from resolvelib.resolvers import Resolution
-
 
 def test_candidate_inconsistent_error():
  requirement = "foo"