TEMPORAL JOINS: "schema.relation.column" does not work for boundaries

[Piiit]

A=# select * from (e as e(x,y,t)                                                                   
full join period with (e.t,public.f.tf) f on x=a and y=b) r ;                                      
ERROR:  invalid reference to FROM-clause entry for table "f"                                       
LINE 2: full join period with (e.t,public.f.tf) f on x=a and y=b) r ...                            
                                   ^                                                               
HINT:  There is an entry for table "f", but it cannot be referenced from this part of the query.   

Belongs to #55.