Test: Add test cases for static DNS processing
Test: Add test cases for static DNS processing

Fixes openbmc/openbmc#2107

Change-Id: Id6810be3527e4861430077364a5af4dc00e52f3b
Signed-off-by: Vishwanatha Subbanna <baa851ce832a3dee6d6d4fecdb8bd9107bb356be@linux.vnet.ibm.com>

openbmc/phosphor-networkd,openbmc/phosphor-networkd