[FIX JENKINS-31015] Prevent InvalidPathException in FileVF

Intentionally leaving out post 1.637 changes in preparation of the
security 1.638 release roll out.

[SECURITY-218] - Functional tests for CLI

[SECURITY-218] Blackbox test

remove unused import statements

In addition to cluttering the namespace, unused imports generate
compiler warnings, introducing noise and obscuring more important
compiler warnings.  This change removes them.

Trying to touch userContent rather than some random file, so that we can verify the result remotely.
Reducing rounds to two: one for capability, one for random transport commands.

This is intended to be a true blackbox test: while we customize the client behavior, it can run against any server.