This code was originally added to force a client render after receiving
an error during hydration. Later we added the ForceClientRender to
implement the same behavior, but scoped to an individual Suspense
boundary instead of all the boundaries in the entire root. So it's
now redudant.
We had some test coverage already but I added another test specifically
for the case of throwing a recoverable hydration error in the shell.
Andrew Clark
79ed5e18fd