refactor: simplify __DEV__ HMR registration and remove isSingleRoot from async component creation.

Author: edison1105

packages/runtime-vapor/src/apiDefineAsyncComponent.ts

@@ -181,12 +181,14 @@ function createInnerComp(
   parent: VaporComponentInstance & TransitionOptions,
   frag?: DynamicFragment,
 ): VaporComponentInstance {
-  const { rawProps, rawSlots, isSingleRoot, appContext, $transition } = parent
+  const { rawProps, rawSlots, appContext, $transition } = parent
   const instance = createComponent(
     comp,
     rawProps,
     rawSlots,
-    isSingleRoot,
+    // rawProps is shared and already contains fallthrough attrs.
+    // so isSingleRoot should be undefined
+    undefined,
     undefined,
     appContext,
   )

packages/runtime-vapor/src/component.ts

@@ -272,14 +272,12 @@ export function createComponent(
   const prevSlotConsumer = setCurrentSlotConsumer(null)
 
   // HMR
-  if (__DEV__ && component.__hmrId) {
+  if (__DEV__) {
     registerHMR(instance)
     instance.isSingleRoot = isSingleRoot
     instance.hmrRerender = hmrRerender.bind(null, instance)
     instance.hmrReload = hmrReload.bind(null, instance)
-  }
 
-  if (__DEV__) {
     pushWarningContext(instance)
     startMeasure(instance, `init`)