Currently, if an ngcc process is killed in a manner that it doesn't clean
up its lock file (or is killed too quickly) the compiler reports that it
is waiting on the PID of a process that doesn't exist, and that it will
wait up to a maximum of N seconds. This PR updates the locking code to
additionally check if the process exists, and if it does not it will
immediately bail out, and print the location of the lock file so a user
may clean it up.
PR Close#37250
561c0f81a0