Recognizer for when a given list of lists of terms calls only
:logic-mode function symbols
For a list x of lists of terms in worldwrld, (logic-fns-list-listp x wrld) is true if and only if every
function symbol called in x is in :logic mode in wrld.
Unlike logic-term-list-listp, logic-fns-list-listp does not check
that x is a list of lists of terms; rather, logic-fns-list-listp
should only be applied to such lists. See defun-mode-lambdas for some
clarifications of how :program mode functions are allowed in certain
:logic mode terms.