ARE NOT BEING HONORED

max_allowed_packet works in conjunction with net_buffer_length.
max_allowed_packet is an upper bound of net_buffer_length.
So it doesn't make sense to set the upper limit lower than the value.
Added a warning (using ER_UNKNOWN_ERRROR and a specific message)
when this is done (in the log at startup and when setting either 
max_allowed_packet or the net_buffer_length variables)
Added a test case.
Fixed several tests that broke the above rule.