Improvements to the CLI tarball validation tests: (#1954)
Improvements to the CLI tarball validation tests: (#1954)

1. Print each command that will be run before it is run (to aid in debugging)
2. Use a new, distinct network for each instance. This prevents issues
   caused by incompatible firewall rules on the `datalab-network` network.
googledatalab/datalab,googledatalab/datalab,parthea/datalab,googledatalab/datalab,parthea/datalab,parthea/datalab,parthea/datalab,parthea/datalab,googledatalab/datalab,googledatalab/datalab,parthea/datalab,googledatalab/datalab