I'm about to refactor part of the commit phase to use recursion instead
of iteration. As part of that change, we will no longer assign the
`return` pointer when traversing into a subtree. So I'm disabling
the internal warning that fires if the return pointer is not consistent
with the parent during the commit phase.
I had originally added this warning to help prevent mistakes when
traversing the tree iteratively, but since we're intentionally switching
to recursion instead, we don't need it.
Andrew Clark
ea7b2ec289