LU-12410 tests: Add gni tests to sanity-lnet

LU-12410 tests: Add gni tests to sanity-lnet

Add test-cases to validate handling of gni nids to sanity-lnet.sh

Also add some additional tests to validate error handling.

Test-Parameters: trivial
Test-Parameters: testlist=sanity-lnet
Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: I7947e237e0d3e12e2e30752bca384cef2b66072c
Reviewed-on: https://review.whamcloud.com/35506
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>