MismatchedTokenError when empty tuple has commented out line

[apmorton]

Given code like:

a = (
    # foo,
)

get_patched_ast will incorrectly scan past the empty tuple and cause MismatchedTokenError.

The following test case will blow up in _consume_pattern because it does not match the pattern

    def test_empty_tuple_node4(self):
        source = "a = (\n# foo,\n)"
        ast_frag = patchedast.get_patched_ast(source, True)
        checker = _ResultChecker(self, ast_frag)
        checker.check_children("Tuple", ["()"])