Fixed #32609 -- Updated runtests.py to support directory path test labels.

For example, with this change, the following now works from the tests
directory:

    $ ./runtests.py view_tests/tests/

1 files changed, 2 insertions, 2 deletions

diff --git a/django/test/runner.py b/django/test/runner.py
index 71bee37297..ee570b0892 100644
--- a/django/test/runner.py
+++ b/django/test/runner.py
@@ -629,8 +629,8 @@ class DiscoverRunner:
                 assert tests is None
                 raise RuntimeError(
                     f'One of the test labels is a path to a file: {label!r}, '
-                    f'which is not supported. Use a dotted module name '
-                    f'instead.'
+                    f'which is not supported. Use a dotted module name or '
+                    f'path to a directory instead.'
                 )
             return tests