Follow up from https://github.com/facebook/react/pull/11616.

Here's one I found. These two invariants:

https://github.com/facebook/react/blob/7e7127387ba64f57299eaff8656542cea6fb3a2d/packages/react-reconciler/src/ReactFiberClassComponent.js#L330-L343

are in a function that's behind a DEV block:

https://github.com/facebook/react/blob/7e7127387ba64f57299eaff8656542cea6fb3a2d/packages/react-reconciler/src/ReactFiberClassComponent.js#L447-L449

I don't think this is intentional, but need to verify.

There may be more. I'll use this issue to track while https://github.com/facebook/react/pull/11616 preserves existing behavior.
const e = await render(<div>{false}</div>);
        expect(e.childNodes.length).toBe(0);
      });
      itRenders('undefined single child as blank', async render => {
        const e = await render(<div>{undefined}</div>);
        expect(e.childNodes.length).toBe(0);
      });
      itRenders('a null component children as empty', async render => {
        const NullComponent = () => null;
        const e = await render(
          <div>
            <NullComponent />
          </div>,
        );
        expect(e.childNodes.length).toBe(0);
      });
      itRenders('null children as blank', async render => {
        const e = await render(<div>{null}foo</div>);
        expect(e.childNodes.length).toBe(1);
        expectTextNode(e.childNodes[0], 'foo');
      });
      itRenders('false children as blank', async render => {
        const e = await render(<div>{false}foo</div>);
        expect(e.childNodes.length).toBe(1);
        expectTextNode(e.childNodes[0], 'foo');
      });
      itRenders('null and false children together as blank', async render => {
        const e = await render(
          <div>
            {false}