fix(runtime-vapor): fix vFor bugs

Author: edison1105

packages/runtime-vapor/__tests__/for.spec.ts

@@ -778,7 +778,7 @@ describe('createFor', () => {
       )
     })
 
-    test.todo('prepend', async () => {
+    test('prepend', async () => {
       const arr = ref<number[]>([4, 5])
       const { host, html } = render(arr)
       expect(host.children.length).toBe(2)

packages/runtime-vapor/src/apiCreateFor.ts

@@ -196,12 +196,15 @@ export const createFor = (
             endOffset++
             continue
           }
-          if (endOffset !== 0) {
-            anchorFallback = normalizeAnchor(newBlocks[currentIndex + 1].nodes)
-          }
           break
         }
 
+        if (endOffset !== 0) {
+          anchorFallback = normalizeAnchor(
+            newBlocks[newLength - endOffset].nodes,
+          )
+        }
+
         while (startOffset < sharedBlockCount - endOffset) {
           const currentItem = getItem(source, startOffset)
           const currentKey = getKey(...currentItem)