cubicweb #2944813 drop unused reset_schema and reset_vreg config on CubicwebTestcase [validation pending]

They are not used by anyone anymore. And they existence justify a more complexe initialisation stack for repo and published.

prioritynormal
typeenhancement
done in3.19.0
load0.250
load left0.000
closed by#c1d5e8ca15ea remove vreg argument to CWPublisher
patchremove vreg argument to CWPublisher [applied][devtools] vreg becomes a class ppty [applied][devtools] drop unused `reset_schema` and `reset_vreg` class attribute [applied]