The rerefreserv_raidz test was failing on Linux because the sync being
issued doesn't guarantee a pool sync. Switch to using the sync_pool
function and remove the ZTS exception for Linux.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#12897
9ba5d8d204