LU-10994 test: remove netdisk from obdfilter-survey

LU-10994 test: remove netdisk from obdfilter-survey

Remove the netdisk case from obdfilter-survey. Remove subtests that
use echo_client over osc devices.

Lustre-change: https://review.whamcloud.com/47239
Lustre-commit: 51c491dac6aec99fc328732b4358e8d5732dc230

Signed-off-by: John L. Hammond <jhammond@whamcloud.com>
Change-Id: I260001241cee3027f68e62077e5817221bd0c08b
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49413
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>