Host `TNode` was passed into `getOrCreateTNode` just so that we can
compute weather or not we are a root node. This was needed because
`previousOrParentTNode` could have `TNode` from `TView` other then
current `TView`. This is confusing mental model. Previous change
ensured that `previousOrParentTNode` must always be part of `TView`,
which enabled this change to remove the unneeded argument.
PR Close#38707