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(<text textlength="10" />, 1);
        expect(e.getAttribute('textLength')).toBe('10');
      });
      itRenders('no badly cased aliased SVG attribute alias', async render => {
        const e = await render(<text strokedasharray="10 10" />, 1);
        expect(e.hasAttribute('stroke-dasharray')).toBe(false);
        expect(e.getAttribute('strokedasharray')).toBe('10 10');
      });
      itRenders(
        'no badly cased original SVG attribute that is aliased',
        async render => {
          const e = await render(<text stroke-dasharray="10 10" />, 1);
          expect(e.getAttribute('stroke-dasharray')).toBe('10 10');
        },
      );
    });
    describe('unknown attributes', function() {
      itRenders('unknown attributes', async render => {
        const e = await render(<div foo="bar" />);
        expect(e.getAttribute('foo')).toBe('bar');
      });
      itRenders('unknown data- attributes', async render => {
        const e = await render(<div data-foo="bar" />);
        expect(e.getAttribute('data-foo')).toBe('bar');
      });
      itRenders('badly cased reserved attributes', async render => {
        const e = await render(<div CHILDREN="5" />, 1);
        expect(e.getAttribute('CHILDREN')).toBe('5');
      });
      itRenders('"data" attribute', async render => {