DSL: Fixed a bug in the delay() function where values could get
dropped if data points for different entities and different dates were
delayed and landed on the same date. This would happen if for example two
companies had values on dates Dec. 31st and Dec. 30th, and these values were
delayed by evaluating signal.delay(months=2). Both values should have ended
up on Feb. 28th, but the bug caused one of the values to be dropped. This would
happen if the signal was evaluated for multiple entities at the same time, such
as in dashboard tables, or alpha tests, but not in pop-up charts or most
drill-downs.