INT 31 P - DPMI 0.9+ - RESIZE MEMORY BLOCK
        AX = 0503h
        BX:CX = new size in bytes (nonzero)
        SI:DI = handle of memory block
Return: CF clear if successful
            BX:CX = new linear address
            SI:DI = new handle of memory block
        CF set on error
            AX = error code (DPMI 1.0+) (8012h-8014h,8016h,8021h,8023h)
                (see AX=0000h)
Notes:  any selectors pointing at the block must be updated
        the previous memory block handle becomes invalid
        an error is returned if the new size is 0
SeeAlso: AX=0501h,AX=0505h