Add more tests for restricted broadcasts.

Test that certain wifi broadcasts are properly protected by the system.
This detects the presence of a security bug which allows the modification
of wifi proxy settings.

This list was taken from frameworks/base commit
47918ae3b4e7ebb54711884e9ff9d0300591ab8b

Public Bug: http://code.google.com/p/android/issues/detail?id=40506
Bug: 7622253

Change-Id: I417e055174f4105c94abdd63de8262f2afd8ea64