qvm-sync-clock in dom0 now synchronize only dom0 time. For VM time,
qvm-sync-clock needs to be called in VM. Also, both will communicate
with qubesd, so must be called asynchronously from tests.
Changed the inheritance hierarchy:
1. Renamed `SystemTestsMixin` to `SystemTestCase`
2. `SystemTestCase` is a child of `QubesTestCase`
3. All classes extending the prior `SystemTestsMixin` now just extend `object`
Check if exit code retrieved from dom0 is really the one expected.
Fix typo in test_065_qrexec_exit_code_vm (testvm1/testvm2), adjust for
reporing remote exit code and remove expectedFailure.
QubesOS/qubes-issues#2861
Since tests expose qubesd socket, qvm-start-gui should handle starting
GUI daemons (so, GUI session inside VM). Add synchronization with it
using qubes.WaitForSession service.
When test expect to wait for remote process, use vm.run_for_stdio.
Additionally, when the call fail, (stdout, stderr) is not assigned - use
the one attached to exception object instead.
Since run_for_stdio raise an exception for non-zero exit code, it isn't
ignored anymore. So, check if qrexec-client-vm return expected value,
instead of keep ignoring it.
QubesOS/qubes-issues#2861
