Probably invalid methods in the context of BacktestingBroker

[majdzadeh]

BacktestingBroker inherits from Broker. Broker exposes the following methods:

• wait_for_order_registration()
• wait_for_order_execution()
• wait_for_orders_registration()
• wait_for_orders_execution()

The above are callable on a backtesting strategy via, for example, self.broker.wait_for_order_registration(). The invocation of the above methods from a backtesting strategy causes the backtesting to freeze.