Use virtual instead of profile time for vmprofile
Use virtual instead of profile time for vmprofile

Avoids infinite looping due to system call restarts
triggered by SIGPROF handling.

Virtual time doesn't account for time spent in the
kernel handling system calls but Snabb tries to avoid
spending time in system calls.

(cherry picked from commit c4681a6c59f705fc49368bc1ae8fdc3fbbeee685)

Igalia/snabb,Igalia/snabb,Igalia/snabb,alexandergall/snabbswitch,eugeneia/snabb,snabbco/snabb,Igalia/snabbswitch,Igalia/snabbswitch,eugeneia/snabb,Igalia/snabb,alexandergall/snabbswitch,snabbco/snabb,snabbco/snabb,snabbco/snabb,alexandergall/snabbswitch,SnabbCo/snabbswitch,SnabbCo/snabbswitch,Igalia/snabb,alexandergall/snabbswitch,alexandergall/snabbswitch,alexandergall/snabbswitch,SnabbCo/snabbswitch,Igalia/snabbswitch,snabbco/snabb,snabbco/snabb,eugeneia/snabb,Igalia/snabb,eugeneia/snabb,Igalia/snabbswitch,alexandergall/snabbswitch,Igalia/snabb,eugeneia/snabb,snabbco/snabb,eugeneia/snabb,eugeneia/snabb,eugeneia/snabb,alexandergall/snabbswitch,snabbco/snabb,Igalia/snabb,Igalia/snabbswitch,SnabbCo/snabbswitch