Fix enableTransitionTracing flag (#24801)

Move `enableTransitionTracing` to `dynamicFeatureFlags` so it runs when you run `yarn test`

packages/react-noop-renderer/src/createReactNoop.js

@@ -806,6 +806,7 @@ function createReactNoop(reconciler: Function, useMutation: boolean) {
           false,
           '',
           onRecoverableError,
+          null,
         );
         roots.set(rootID, root);
       }
@@ -859,6 +860,7 @@ function createReactNoop(reconciler: Function, useMutation: boolean) {
         false,
         '',
         onRecoverableError,
+        null,
       );
       return {
         _Scheduler: Scheduler,

packages/react-reconciler/src/ReactFiber.new.js

@@ -734,6 +734,9 @@ export function createFiberFromLegacyHidden(
   const fiber = createFiber(LegacyHiddenComponent, pendingProps, key, mode);
   fiber.elementType = REACT_LEGACY_HIDDEN_TYPE;
   fiber.lanes = lanes;
+  // Adding a stateNode for legacy hidden because it's currently using
+  // the offscreen implementation, which depends on a state node
+  fiber.stateNode = {};
   return fiber;
 }
 

packages/react-reconciler/src/ReactFiber.old.js

@@ -734,6 +734,9 @@ export function createFiberFromLegacyHidden(
   const fiber = createFiber(LegacyHiddenComponent, pendingProps, key, mode);
   fiber.elementType = REACT_LEGACY_HIDDEN_TYPE;
   fiber.lanes = lanes;
+  // Adding a stateNode for legacy hidden because it's currently using
+  // the offscreen implementation, which depends on a state node
+  fiber.stateNode = {};
   return fiber;
 }
 

packages/react/index.classic.fb.js

@@ -34,6 +34,7 @@ export {
   startTransition,
   startTransition as unstable_startTransition, // TODO: Remove once call sights updated to startTransition
   unstable_Cache,
+  unstable_TracingMarker,
   unstable_DebugTracingMode,
   unstable_LegacyHidden,
   unstable_Offscreen,

packages/shared/forks/ReactFeatureFlags.www.js

@@ -33,6 +33,7 @@ export const {
   enableSyncDefaultUpdates,
   enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay,
   enableClientRenderFallbackOnTextMismatch,
+  enableTransitionTracing,
 } = dynamicFeatureFlags;
 
 // On WWW, __EXPERIMENTAL__ is used for a new modern build.
@@ -106,8 +107,6 @@ export const enableUseMutableSource = true;
 
 export const enableCustomElementPropertySupport = __EXPERIMENTAL__;
 
-export const enableTransitionTracing = false;
-
 export const enableSymbolFallbackForWWW = true;
 // Flow magic to verify the exports of this file match the original version.
 // eslint-disable-next-line no-unused-vars