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.
<div />
          </div>,
        ));
      it('should error reconnecting reordered children', () =>
        expectMarkupMismatch(
          <div>
            <div />
            <span />
          </div>,
          <div>
            <span />
            <div />
          </div>,
        ));
      it('should error reconnecting a div with children separated by whitespace on the client', () =>
        expectMarkupMismatch(
          <div id="parent">
            <div id="child1" />
            <div id="child2" />
          </div>,
          
          <div id="parent"><div id="child1" />      <div id="child2" /></div>, 
        ));
      it('should error reconnecting a div with children separated by different whitespace on the server', () =>
        expectMarkupMismatch(
          
          <div id="parent"><div id="child1" />      <div id="child2" /></div>, 
          <div id="parent">
            <div id="child1" />
            <div id="child2" />