Fixes the tests in #1781.

There are a few alternative ways to do fix those tests (and some things wrong with this one)

Solution 1 - This one! Save the original ROOT node tree, and use in calls to parents etc

• The saved root node tree will not actually match the ROOT node tree after root update. updates will affect the ROOT node tree but not the saved tree. This is already sort of the case, currently updates to the ROOT (for example setting state) would not affect childWrapper[NODES], but would modify childWrapper[ROOT][NODES]. Given that we want child wrappers to be immutable I think this might make the most sense.
• It is possible here for something to still accidentally compare between the old and new tree by using .root().getNodeInternal() instead of getRootNodeInternal()

Solution 2 - On update we swap all child wrappers ROOTs to a copy of the old root.

• Calling and methods that update the parent would no longer work after an update. Ie

const child = wrapper.find(Child);
wrapper.find(...) // Or anything that calls update on the wrapper
child.simulate(...) // Would affect the copy, not the real wrapper

Solution 3 - Make child wrappers not able to cause updates

• Breaking change, makes simulating child events and setting child state etc not possible

Solution 4 - Make child wrappers not immutable and update with component updates

• 🤷‍♂️

@ljharb