RAW_NS used previous a single TTCN3 port for a single UDP port
(source/listen side).
This has the limitation that only a single NSVC could be tested for a
local UDP port. However SNS tests require multiple NSVCs over a single UDP port.
NS_Provider_IPL4 already supports multiple NSVCs for the NS_Emulation.
Extend the support in NS_Provider_IPL4 to also allow RAW_NS to use
multiple NSVCs.
Related: OS#5036
Change-Id: Iafd9310e04066958914201da0cbdcd563bd5c976
Alexander Couzens