gh-116609: Ignore UTF-16 BOM in importlib.resources._functional tests
To test the `errors` argument, we read a UTF-16 file as UTF-8
with "backslashreplace" error handling. However, the utf-16
codec adds an endian-specific byte-order mark, so on big-endian
machines the expectation doesn't match the test file (which was
saved on a little-endian machine).
Use endswith to ignore the BOM.
gh-116307: Create a new import helper 'isolated modules' and use that instead of 'Clean Import' to ensure that tests from importlib_resources don't leave modules in sys.modules.
* gh-95218: Move tests for importlib.resources into test_importlib.resources.
* Also update makefile
* Include test_importlib/resources in code ownership rule.
* bpo-45514: Apply changes from importlib_resources@a3ef4128c6
* Mark legacy functions as deprecated in the docs and link to the migration docs in importlib_resources docs.
* Apply changes from importlib_resources@329ae9d5f2c.
* Indicate importlib.resources as a module.
Co-authored-by: Filipe Laíns <lains@riseup.net>
Petr Viktorin
Jason R. Coombs