Convert SettingsLib tests to Android.bp

See build/soong/README.md for more information.

Bug: 122332340
Test: m RunSettingsRoboTests
Test: atest SettingsLibTests (same failures before and after)
Change-Id: I69b5b2c6c22f93a31ef978710867226cb1ba3db0
Merged-In: I69b5b2c6c22f93a31ef978710867226cb1ba3db0