Reduce race when connecting to an existing content provider.

We lost the code that checks to see if the target process still
exists and aborts trying to use it if so.  To reduce the race
there, we have a new explicit check of the state of the process.

Hopefully fixes some of issue #28737082.

Change-Id: I37a7a6e9767516d564168ef5e110c4adafe3fb76