[3.5] bpo-29887: Test normalization now fails if download fails (GH-905) (#2272)

[3.5] bpo-29887: Test normalization now fails if download fails (GH-905) (#2272)

* [3.5] bpo-29887: Test normalization now fails if download fails (GH-905)

* test_normalization fails if download fails

bpo-29887. The test is still skipped if "-u urlfetch" option is not
passed to regrtest (python3 -m test -u urlfetch test_normalization).

* Fix ResourceWarning in test_normalization

bpo-29887: Fix ResourceWarning in test_normalization if tests are
interrupted by CTRL+c.
(cherry picked from commit 722a3af092b94983aa26f5e591fb1b45e2c2a0ff)

* bpo-29887: test_normalization handles PermissionError (#1196)

Skip test_normalization.test_main() if download raises a permission
error.
(cherry picked from commit d13d54748d3a7db023d9db37223ea7d40bb8f8e3)

* no f-strings :(