(PUP-867) Remove support for dynamic defaults for future parser

WHen future parser is in effect, the lookup of default values
will now not look in "parent scopes" (i.e. scopes that *contain*
the resource). Instead it now only looks in inherited and enclosing
scopes + itself.

This removes the confusion that occurs when a class may be included
from different locations, and the location that wins manages to impose
the defaults from its scope.

This removal goes hand in hand with dynamic scoping being removed
everywhere else.