ground engine executions

[MaxOstrowski]

In the ground-engine case set/executions, there are 2 expressions with more than 1 true _se_value(expr, value):

variable(execution_output(exec_external,external_out))

• bad
• ref(set,variable(execution_output(exec_external,external_out)))

and
operation(set_isin,(val(int,2),(variable(execution_output(exec_external,external_out)),())))

• val(bool,false)
• val(bool,true)