Merge Dep_node_without_state into Dep_node (#8936)

It seems that [Dep_node_without_state] doesn't actually need to exist so
this merges it nto [Dep_node]. The main drawback is that more modules need
to be mutually recursive now so the bulk of this PR just moves things
around to make that happen. The resulting code still seems clearer to me
and also seems to be slightly more efficient since we remove 2 words (I
think) and 1 indirection from each [Dep_node].

Signed-off-by: Roman Leshchinskiy <[email protected]>
Co-authored-by: Roman Leshchinskiy <[email protected]>
Co-authored-by: Andrey Mokhov <[email protected]>