run vndk-sp closure check before double-loadable

If vndk-sp closure fails, the error message mentions it instead of
double-loadable error. It would be more helpful since vndk-sp is more
straightforward to fix.

Bug: 171080110
Test: m (soong test added)
Change-Id: Icc762a4ffb4a8d7d6b31ef1daac17f13383518bf