In Strict Mode, function component and class component are inconsistent with scenes that produce side effects

<!-- Please provide a clear and concise description of what the bug is. Include screenshots if needed. Please test using the latest version of the relevant React packages to make sure your issue has not already been fixed. --> React version: 17.0.2 ## Steps To Reproduce ```js import React from 'react'; const TestFunc = () => { debugger const myRef = React.useRef(true) if (myRef.current) { myRef.current = false } return <div>666</div> } class TestClass extends React.Component { myRef = React.createRef() constructor(props) { super(props); this.myRef.current = true } render() { debugger if (this.myRef.current) { this.myRef.current = false } return <div>888</div> } } function App() { return ( <React.StrictMode> <TestFunc /> <TestClass /> </React.StrictMode> ); } export default App; ``` 1. Use strict mode 2. Observe the changes of the myRef.current variable when the two components are rendered for the second time 3. In the function component, the value of the myRef.current variable is "true" in the two renders before and after, so the two renders will go to the "myRef.current = false" logic. But in the class component, when rendering twice, the myRef.current variable is "true" in the first rendering, but the "false" that was modified in the first rendering is retained in the second rendering. Reason: I looked at the source code and found that for the function component, although renderWithHooks was called twice before and after and the same workInProgress was used, but every time in the "renderWithHooks" method, the value of "workInProgress.memoizedState" is set to null, and in the useRef function of the mounting phase, the "workInProgress.memoizedState" property on "alternate" will not be reused, therefore, in the mounting phase in strict mode, during the second rendering, the state saved by ref during the first rendering cannot be obtained in the function component. ![4641640144553_ pic…