Fix selftest for genyang
Fix selftest for genyang

Don't generate values with invalid ranges or types
for the selftest to ensure the test is predictable.

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