PR# 19993 Once classes: once-per-process in SCOOP mode

When in SCOOP mode, if the creation procedure of a once class is a once-per-process procedure, the type of corresponding creation instructions and creation expressions should be declared as separate. This was discussed at the bottom of this page: https://www.eiffel.org/blog/Alexander%20Kogtenkov/2020/12/once-classes
But the EiffelStudio compiler fails to report the error.

--
Eric Bezault

class AA

create

	make,
	make_separate

feature

	make
		local
			b: BB
			a: separate AA
		do
			create b.make
			create a.make_separate
		end

	make_separate
		local
			b: BB
		do
			create b.make
		end

end
~~~~~~
once class BB

create

	make

feature

	make
		once ("PROCESS")
		end

end