For consideration.

These warnings are already covered by renderers based on react-reconciler. Maybe we don't gain that much by mirroring them in the shallow renderer? Maybe it's not worth the added complexity? Particularly with more complicated warnings like the ones being added for #12419 and #12404.
constructor(props, context) {
        super(props, context);
        this.state = {
          hasUpdatedState: false,
        };
      }
      UNSAFE_componentWillMount() {
        this.setState(
          {hasUpdatedState: true},
          () => (stateSuccessfullyUpdated = this.state.hasUpdatedState),
        );
      }
      render() {
        return <div>{this.props.children}</div>;
      }
    }
    const shallowRenderer = createRenderer();
    shallowRenderer.render(<Component />);
    expect(stateSuccessfullyUpdated).toBe(true);
  });
  it('should handle multiple callbacks', () => {
    const mockFn = jest.fn();
    const shallowRenderer = createRenderer();
    class Component extends React.Component {