fix(runtime-core): support object syntax for class (#215)

packages/runtime-core/src/vnode.ts

@@ -4,8 +4,7 @@ import {
   isString,
   isObject,
   EMPTY_ARR,
-  extend,
-  PatchFlags
+  extend
 } from '@vue/shared'
 import {
   ComponentInternalInstance,
@@ -146,9 +145,7 @@ export function createVNode(
     if (isReactive(props) || SetupProxySymbol in props) {
       props = extend({}, props)
     }
-    // class normalization only needed if the vnode isn't generated by
-    // compiler-optimized code
-    if (props.class != null && !(patchFlag & PatchFlags.CLASS)) {
+    if (props.class != null) {
       props.class = normalizeClass(props.class)
     }
     let { style } = props