Merge pull request #12816 from gpnaveen/stc_rte_err_msg

tests: Enhance error msgs for static route automation.

diff --cc tests/topotests/static_routing_with_ebgp/test_static_routes_topo1_ebgp.py
Simple merge

diff --cc tests/topotests/static_routing_with_ebgp/test_static_routes_topo2_ebgp.py
Simple merge

diff --cc tests/topotests/static_routing_with_ebgp/test_static_routes_topo3_ebgp.py
Simple merge

diff --cc tests/topotests/static_routing_with_ebgp/test_static_routes_topo4_ebgp.py
Simple merge

diff --cc tests/topotests/static_routing_with_ibgp/test_static_routes_topo1_ibgp.py
Simple merge

diff --cc tests/topotests/static_routing_with_ibgp/test_static_routes_topo2_ibgp.py
Simple merge

diff --cc tests/topotests/static_routing_with_ibgp/test_static_routes_topo3_ibgp.py
Simple merge

diff --cc tests/topotests/static_routing_with_ibgp/test_static_routes_topo4_ibgp.py
Simple merge