Require apps built against the SDK to use JNI built against the NDK

Apps that expect to run on older platforms should use JNI libraries
that will also run on older platforms.  Require that apps that set
sdk_version have jni_libs modules that also set sdk_version, or
set jni_uses_platform_apis: true to bypass the check.

Fixes: 149591057
Test: app_test.go
Change-Id: I76b9b45fb5773bc4dfc10520108f4f3578723909