[tests] Fix flaky flight tests (facebook#35513)

Flights tests are failing locally and in CI non-deterministically
because we're not disabling async hooks after tests, and GC can clear
WeakRefs non-deterministically.

This PR fixes the issue by adding an afterEach to disable installed
hooks, and normalizing the `value` to `value: {value: undefined}}` when
snapshotting.

Author: rickhanlonii

packages/internal-test-utils/debugInfo.js

@@ -79,6 +79,18 @@ function normalizeIOInfo(config: DebugInfoConfig, ioInfo) {
         status: promise.status,
       };
     }
+  } else if ('value' in ioInfo) {
+    // If value exists in ioInfo but is undefined (e.g., WeakRef was GC'd),
+    // ensure we still include it in the normalized output for consistency
+    copy.value = {
+      value: undefined,
+    };
+  } else if (ioInfo.name && ioInfo.name !== 'rsc stream') {
+    // For non-rsc-stream IO that doesn't have a value field, add a default.
+    // This handles the case where the server doesn't send the field when WeakRef is GC'd.
+    copy.value = {
+      value: undefined,
+    };
   }
   return copy;
 }

scripts/jest/setupTests.js

@@ -319,3 +319,14 @@ jest.mock('async_hooks', () => {
     },
   };
 });
+
+// Ensure async hooks are disabled after each test to prevent cross-test pollution.
+// This is needed because test files that load the Node server (with async debug hooks)
+// can pollute test files that load the Edge server (which doesn't create new hooks
+// to trigger the cleanup in the mock above).
+afterEach(() => {
+  if (installedHook) {
+    installedHook.disable();
+    installedHook = null;
+  }
+});