Don't send package stats on bundle.

Send them only on 'run' (which is likely to be running for a long time,
giving us plenty of time to send stats) and 'deploy' (which has to go
over the network anyway), though we don't wait for stats to be sent
before exiting from any commands.

Update stats self-test to run apps instead of bundling them. Add an
environment variable to print some output about when package stats have
been sent for the test to know when it's okay to stop the 'meteor run'
process.