rump kernel tests: Run xenstore-ls demo

rump kernel tests: Run xenstore-ls demo

We can use the newly-generalised ts-rumpuserxen-demo-setup to set up
the config file etc. to run xenstore-ls from the xen.git build.

We have a bespoke script to actually execute it: we extract the actual
program output from the guest console log, and compare the results to
those we expect (based on running xenstore-ls in dom0).

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
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v2: Fix copyright date in new script.