The jsx-runtime uses the ReactCurrentDispatcher from shared internals.
Recently this was moved to ReactServerSharedInternals which broke
jsx-runtime. This change moves it back to ReactSharedInternals until we
can come up with a new forking mechanism.
DiffTrain build for commit https://github.com/facebook/react/commit/6f132439578ee11e04b41a278df51c52b0dc8563.