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.
expectNode(spanNode.firstChild, TEXT_NODE_TYPE, 'More Text');
      });
      itRenders('a non-standard element with text', async render => {
        const e = await render(<nonstandard>Text</nonstandard>);
        expect(e.tagName).toBe('NONSTANDARD');
        expect(e.childNodes.length).toBe(1);
        expectNode(e.firstChild, TEXT_NODE_TYPE, 'Text');
      });
      itRenders('a custom element with text', async render => {
        const e = await render(<custom-element>Text</custom-element>);
        expect(e.tagName).toBe('CUSTOM-ELEMENT');
        expect(e.childNodes.length).toBe(1);
        expectNode(e.firstChild, TEXT_NODE_TYPE, 'Text');
      });
      itRenders('a leading blank child with a text sibling', async render => {
        const e = await render(<div>{''}foo</div>);
        if (render === serverRender || render === streamRender) {
          expect(e.childNodes.length).toBe(1);
          expectTextNode(e.childNodes[0], 'foo');
        } else {
          expect(e.childNodes.length).toBe(2);
          expectTextNode(e.childNodes[0], '');
          expectTextNode(e.childNodes[1], 'foo');
        }
      });
      itRenders('a trailing blank child with a text sibling', async render => {
        const e = await render(<div>foo{''}</div>);
        
        if (render === serverRender || render === streamRender) {
          expect(e.childNodes.length).toBe(1);