PR# 20003 Once classes: invalid inspect interval

The validity rule VOIN indicates that an inspect interval cannot be empty.
In the example below, the interval `{BB}.h .. {BB}.f` is empty because `f` appears before `h` in the list of creation procedures of `BB`.

--
Eric Bezault

class AA

create

	make

feature

	make
		local
			b: BB
		do
			create b.g
			inspect b
			when {BB}.h .. {BB}.f then
			else
			end
		end

end
~~~~~~~
once class BB

create

	f, g, h

feature

	f
		once
		end

	g
		once
		end

	h
		once
		end
	
end