cubicweb #2142041 crash on inserting read permission when various rql expr for different solutions [validation pending]

the tree cleanup is broken and lead to and 'x is not in list' error

prioritynormal
typebug
done in3.14.3
load0.100
load left0.000
closed by#335b358c7017 [rql, security]?fix buggy rqlstr cleanup when some introduced snippet create an unresolvable query. Closes #2142041