Revert "Use tox for testing"

This reverts commit e36c09482d.

There are several problems with the reverted commit:

1. The -t option should go to %pyproject_buildrequires, not  %generate_buildrequires.
2. This package is a transitive BuildRequirement for tox itself.
3. This package is in ELN where tox is not desired.
4. This package has no test dependencies, so using tox is overkill.

python-typing-extensions.spec

@@ -44,7 +44,7 @@ Summary:       %{summary}
 %autosetup -n typing_extensions-%{version}
 
 
-%generate_buildrequires -t
+%generate_buildrequires
 %pyproject_buildrequires
 
 
@@ -59,7 +59,8 @@ Summary:       %{summary}
 
 
 %check
-%tox
+cd src
+%{python3} -m unittest discover
 
 
 %files -n python3-typing-extensions -f %{pyproject_files}