fixup! Rename variables 'tmpdir'->'tmp_path'

* Add some more of these
* Also reintroduce+rename instances of fixture usages that were
'tmpdir'->'tmp_path'

testing/python/collect.py

@@ -274,7 +274,7 @@ class TestFunction:
         pytester.makepyfile(
             """
             class A(object):
-                def __call__(self):
+                def __call__(self, tmp_path):
                     0/0
 
             test_a = A()

testing/python/integration.py

@@ -234,7 +234,7 @@ class TestMockDecoration:
             @mock.patch("os.path.abspath")
             @mock.patch("os.path.normpath")
             @mock.patch("os.path.basename", new=mock_basename)
-            def test_someting(normpath, abspath):
+            def test_someting(normpath, abspath, tmp_path):
                 abspath.return_value = "this"
                 os.path.normpath(os.path.abspath("hello"))
                 normpath.assert_any_call("this")