lint: Compute ergonomic name for tests

The command-line interface to Python's "unittest" module allows users to
run tests by name, e.g.

    $ test.py TestLinter.test_foo

If the tests include a period, they cannot be referenced in this way.
Rename the tests to omit the filename extension so that they may be
referenced from the command-line in this way.

tools/lint/test/run.py

@@ -89,6 +89,7 @@ def create_file_test(name, fspath):
             for err in expected:
                 self.assertIn(err, stderr)
 
+    test.__name__ = 'test_' + file_name.split('.')[0]
     return test
 
 dirname = os.path.join(os.path.abspath(testDir), 'fixtures')
@@ -99,7 +100,6 @@ for file_name in os.listdir(dirname):
         continue
 
     t = create_file_test(file_name, full_path)
-    t.__name__ = 'test_' + file_name
     setattr(TestLinter, t.__name__, t)
 
 if __name__ == '__main__':