dts: dynamic config test suite

[Luca Vizzarro]

Can you please rebase this on the latest changes, as the code will look 
different for sure?

Three comments in the meantime:

  * Is there a reason for sleeping for 6 seconds? If so could you please
    explain it?
  * Please follow naming standards consistently, variables should be in
    snake_case, referring to isPromisc -> is_promisc
  * Please follow contributing guidelines when writing your commit
    subject and body[1]
      o Example I can spot are capitalisation of wording and the
        non-imperative subject

Thanks,

Luca

[1] 
https://doc.dpdk.org/guides/contributing/patches.html#commit-messages-subject-line