Relocate static function declarations to be after typedefs in jsonfuncs.c.

Project style is to put things in this order, for the good and sufficient
reason that you often need the typedefs in the function declarations.
There already was one function declaration that needed a typedef, which
was randomly placed away from all the other static function declarations
in consequence.  And the submitted patch for better json_populate_record
functionality jumped through even more hoops in order to preserve this
bad idea.

This patch only moves lines from point A to point B, no other changes.