Remove the SDK check and update test runner

The tests are in the platform now so the SDK check is no longer
needed. Also update test runner since the tests do not need to
use DevSdkIgnoreRunner so update it to AndroidJUnit4 instead.

Test: atest FrameworksVpnTests
Change-Id: Ibbd475820d87fd189f76b0134c688d52a0139451
3 files changed