init: handle process actions when waiting for exec services

We currently do not handle process actions (restarting services or
exiting timedout services) when we are waiting for an exec service,
but this seems to be the wrong behavior.  Particularly, an exec
service may depend on a previously started service and if that service
crashes, we will deadlock unless init restarts it.

Bug: 146920034
Test: build, boot
Change-Id: Id2fc936b8a7b989862ba4c32c398a544941e0e76