dillon1000/react

Reused components commit with timing as new ones

When an Offscreen tree goes from hidden -> visible, the tree may include
both reused components that were unmounted when the tree was hidden, and
also brand new components that didn't exist in the hidden tree.

Currently when this happens, we commit all the reused components'
effects first, before committing the new ones, using two separate
traversals of the tree.

Instead, we should fire all the effects with the same timing as if it
were a completely new tree. See the test I wrote for an example.

This is also more efficient because we only need to traverse the
tree once.