RelJson cannot handle timestamps prior to 1970-01-25 20:31:23.648

Because the millisSinceEpoch of 1970-01-25 20:31:23.647 and prior can be stored in an Integer, it results in some failed casts to Long (because we assume all TIMESTAMP and TIMESTAMP WITH LOCAL TIME ZONE will be represented using Long. The fix should be simple enough, as we can check the type and if it is a TIMESTAMP or TIMESTAMP WITH LOCAL TIME ZONE and the value is an Integer, we can use .toLongValue() instead of casting to Long directly.