One swap partition can be shared between several GNU/Linux distributions.
However, I believe hibernation becomes a problem (for sure running another
distribution after hibernating does not allow to recover). Besides
hibernation, the swap can be emptied (although it is not necessary) between
reboots, like the RAM is, and reused by another distribution.
My /etc/fstab has this line because my swap partition is /dev/sda1:
/dev/sda1 none swap sw 0 0
One way to know the number of your swap partition (do not write 1 if it is
not the first partition!):
$ sudo parted -l