Hotfix custom variant (affects chess-in-5d)

Custom variant does not initialize when Chess.reset() is invoked. This problem affects chess-in-5d, causing it to fail to import games with custom variant (which is significant because most pgn recorders record turn zero as a custom variant).

This merge request also fixes two test cases.

The pipeline fails because I do not own a credit card to validate my account. All tests are passed on my machine.