bpo-29887: test_normalization handles PermissionError (python#1196) (python#2275)

Skip test_normalization.test_main() if download raises a permission
error.
(cherry picked from commit d13d547)

Author: vstinner

Lib/test/test_normalization.py

@@ -40,6 +40,9 @@ def test_main(self):
         try:
             testdata = open_urlresource(TESTDATAURL, encoding="utf-8",
                                         check=check_version)
+        except PermissionError:
+            self.skipTest(f"Permission error when downloading {TESTDATAURL} "
+                          f"into the test data directory")
         except (OSError, HTTPException):
             self.fail(f"Could not retrieve {TESTDATAURL}")