[WIFI] Restore initialization code

Restore the usage of WIFI-specific main function. The main
function was inadvertantly disabled by moving it into a static
library - which caused the default main to be used.

Need a custom main since need to stop WIFI before tests start
to enforce a clean starting point.

Bug: 35276551
Test: confirms custom main routine is called
Change-Id: I978827bc0f0f16d9ca4f159fbf42d0bc53f5df99