This renames BLOCKDEV_LIST_IGNORE_ZRAM to BLOCKDEV_LIST_IGNORE_RAMDISK,
and make it ignores both /dev/ramX and /dev/zramX.
Note, linux-stable by Alpine/postmarketOS has CONFIG_BLK_DEV_RAM=y,
hence the kernel creates /dev/ramX by default. Without this change,
the test case added by 236e7d8a4c fails,
as io.systemd.Repart.ListCandidateDevices varlink method lists the
ramdisks.