ZTS: Minimize udev_wait in zvol_misc tests

The zvol_misc tests, in particular zvol_misc_volmode, make use of a
common udev_wait function to wait for zvol devices in /dev to quiesce
on Linux.  On other platforms this function currently only sleeps for
one second before returning.  This is insufficient, and
zvol_misc_volmode has been flaky on FreeBSD as a result.

Replace udev_wait with block_device_wait, passing through the optional
device parameter where possible.  Rearrange a few checks to strengthen
the verifications we are making and avoid unnecessarily sleeping.  We
must keep udev_wait in a couple places to pass in Github CI workflows.
Remove zvol_misc_volmode from the maybe failing tests on FreeBSD in
zts-report.py.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Ryan Moeller <ryan@iXsystems.com>
Closes #12583

tests/zfs-tests/include/blkdev.shlib

@@ -73,7 +73,7 @@ function scan_scsi_hosts
 function block_device_wait
 {
 	if is_linux; then
-		udevadm trigger $*
+		udevadm trigger $* 2>/dev/null
 		typeset start=$SECONDS
 		udevadm settle
 		typeset elapsed=$((SECONDS - start))