Reapply [IR] Mark and/or constant expressions as undesirable

This reapplies the change for and, but also marks or as undesirable
at the same time. Only handling one of them can cause infinite
combine loops due to the asymmetric handling.

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In preparation for removing support for and/or expressions, mark
them as undesirable. As such, we will no longer implicitly create
such expressions, but they still exist.