Strip tests from the installed files

It's a waste of space, plus it causes noarch inconsistency (so,
failed build) now we're wiping one of these in %prep on s390x.

python-dask.spec

@@ -152,6 +152,8 @@ rm -rf html/.{doctrees,buildinfo}
 
 %install
 %pyproject_install
+# we do not want to ship test files
+find %{buildroot}%{python3_sitelib}/%{srcname} -type d -name tests -print0 | xargs -0 rm -rf
 
 %pyproject_save_files %{srcname}