ie exec and eval statements are supposed to start with the future
flags of the scope in which they are called.  Our flags currently
get applied after parsing, which for the most part is fine, except
print_statement which actually changes the result of parsing.

ie `exec "print(1, 2)"` could either be parsed as a function call,
which will print "1 2", or as a print statement of a tuple, which
prints out "(1, 2)".  So thread the future flags through the parsing
stages as well.