Source code and tests for Wifi service have moved to
packages/modules/Wifi/service.

- frameworks/opt/net/wifi/service/apex -> packages/modules/Wifi/apex
- frameworks/opt/net/wifi/service/java -> packages/modules/Wifi/service/java
- frameworks/opt/net/wifi/service/res -> packages/modules/Wifi/service/ServiceWifiResources/res
- frameworks/opt/net/wifi/tests/ -> packages/modules/Wifi/service/tests

What remains in frameworks/opt/net/wifi are Wifi libraries that
are not part of the Wifi module.