LU-12410 tests: Additional test cases for lnetctl and DLC

LU-12410 tests: Additional test cases for lnetctl and DLC

To faciliate the refactoring of a few lnetctl commands I wrote some
additional test cases for sanity-lnet.sh

Test-Parameters: trivial
Test-Parameters: testlist=sanity-lnet
Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: I9f3f74420f89b824ee25b6547c0baa815ccfd948
Reviewed-on: https://review.whamcloud.com/35386
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>