fix(Injection with Symbol polyfill): hasOwn instead of 'in'

Symbol polyfill adds a setter on the Object prototype so the 'in' check evaluated to true on every
object

fix vuejs#7284

src/core/instance/inject.js

@@ -3,6 +3,7 @@
 import { warn } from '../util/index'
 import { hasSymbol } from 'core/util/env'
 import { defineReactive, observerState } from '../observer/index'
+import { hasOwn } from 'shared/util'
 
 export function initProvide (vm: Component) {
   const provide = vm.$options.provide
@@ -52,7 +53,7 @@ export function resolveInject (inject: any, vm: Component): ?Object {
       const provideKey = inject[key].from
       let source = vm
       while (source) {
-        if (source._provided && provideKey in source._provided) {
+        if (source._provided && hasOwn(source._provided, provideKey)) {
           result[key] = source._provided[provideKey]
           break
         }