Suggestion, Hook: Avoid rerender if useReducer's dispatch is called before the hook

[kangaroooh]

Current behaviour
When rendering a component, if I call the dispatch (setState) function of useReducer before I actually call useReducer, it will trigger the component to be rerendered.
This behaviour is demonstrated here, the custom hook's code is copied bellow.

Suggested behaviour
In the current implementation, dispatched actions (and mostly the ones triggered during the render phase) are handled inside useReducer. If the dispatch function is called before useReducer, we don't have to wait to rerender to handle this action.
This new behaviour is demonstrated in the current Pull Request.
I'm not expecting a negative effect because hooks are currently meant to be called always in same order and not conditionally.

Motivation
I came to this change trying to implement a custom hook useDerivedState:

const useDerivedState = (computeDerivedState, inputs, initialState = null) => {
  const setStateRef = useRef(null);
  useMemo(() => {
    if (setStateRef.current) {
      const setState = setStateRef.current;
      setState(prevState => {
        const newState = computeDerivedState(prevState);
        return newState !== undefined ? newState : prevState;
      });
    }
  }, inputs);
  const stateStuff = useState(() => {
    let state = initialState;
    if (typeof state === "function") {
      state = state();
    }
    return computeDerivedState(state);
  });
  [, setStateRef.current] = stateStuff;
  return stateStuff;
};

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Softagram Impact Report for pull/15 (head commit: ff4e7fb)

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💡 Insights

• Co-change Alert: You modified ReactFiberHooks.js. Often ReactHooks-test.internal.js (src/tests) is modified at the same time.

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