Wifi test updates.

Refactor wifi config generation in sl4a to support more security modes.
Refactor wifi tests and utils accordingly.
Simplify message passing by using json directly instead of strings
representing json objects.
Add a stress test that does gscan before rtt ranging.
Simplify wifiConnect in wifi facade.

Change-Id: I1cea8e59cab6888cbc023289ea8e4d138e9c3f5f
3 files changed