* gh-95299: Rework test_cppext.py to not invoke setup.py directly
* Add tests/cppextdata data to `TESTSUBDIRS`
* Revert "Add tests/cppextdata data to `TESTSUBDIRS`"
This reverts commit 635492e539.
* Revert "gh-95299: Rework test_cppext.py to not invoke setup.py directly"
This reverts commit 41c5a667b5.
* Build and install the extension in a temporary directory instead
* Pull in wheels for setuptools and wheel for testing extension builds