Encode fragments properly in DEV

Normally we take the renderClientElement path but this is an internal fast path.

packages/react-server/src/ReactFlightServer.js

@@ -1215,12 +1215,11 @@ function renderFragment(
  if (task.keyPath !== null) {
  // We have a Server Component that specifies a key but we're now splitting
  // the tree using a fragment.
- const fragment = [
- REACT_ELEMENT_TYPE,
- REACT_FRAGMENT_TYPE,
- task.keyPath,
- {children},
- ];
+ const fragment = __DEV__
+ ? enableOwnerStacks
+ ? [REACT_ELEMENT_TYPE, REACT_FRAGMENT_TYPE, task.keyPath, {children}, null, null, 0]
+ : [REACT_ELEMENT_TYPE, REACT_FRAGMENT_TYPE, task.keyPath, {children}, null]
+ : [REACT_ELEMENT_TYPE, REACT_FRAGMENT_TYPE, task.keyPath, {children}];
  if (!task.implicitSlot) {
  // If this was keyed inside a set. I.e. the outer Server Component was keyed
  // then we need to handle reorders of the whole set. To do this we need to wrap