Fix Turbopack scope hoisting so that a merged module's export registration is available before normal module-body execution can transfer control into another scope-hoisting group. This should match the existing behavior for cyclic modules that are not scope hoisted. In a cycle where merged group A enters group B and B re-enters A, the second entry must see A's exports already registered, A must evaluate only once, and direct exports and closures over those exports must observe the same initialized binding.