INT 62 - Cswitch - TEST MESSAGE QUEUE                                           
	AH = 0Ah
	DX = queue number (0-63)
Return: AX = result/message size
	    0000h nothing on queue
	    FFFFh bad queue number
	    else  number of bytes in first message in queue
SeeAlso: AH=0Bh"Cswitch",AH=0Ch"Cswitch"