Fixed following issues in BG96 offloaded DNS:
- Fixed mbed-os 6 API change for asynchronous DNS callback. Return value is no longer
an error value but in success case the amount of DNS records
- Asynchronous request returns request ID instead of NSAPI_ERROR_OK. BG96 supports only
one asynchronouse DNS query at the time, so ID 1 is used.
- BG96 does not support multi-ip DNS responses, so disabled multi-ip tests
New members are added to the network interface
-getaddrinfo
-getaddrinfo_async
gethostbyname is unchanged but gethostbyname_async result param now contains results od DNS records found.
Test cases for sync/async added added to DNS test folder.
Kimmo Vaisanen
Martin Kojtal
Tymoteusz Bloch
Evelyne Donnaes