fix(scheduler): sort jobs before flushing

This fixes the case where a child component is added to the queue before
its parent, but should be invalidated by its parent's update. Same logic
was present in Vue 2.

Properly fixes #910
ref: https://github.com/vuejs/vue-next/issues/910#issuecomment-613097539

packages/runtime-core/__tests__/scheduler.spec.ts

@@ -262,4 +262,20 @@ describe('scheduler', () => {
     // job2 should be called only once
     expect(calls).toEqual(['job1', 'job2', 'job3', 'job4'])
   })
+
+  test('sort job based on id', async () => {
+    const calls: string[] = []
+    const job1 = () => calls.push('job1')
+    // job1 has no id
+    const job2 = () => calls.push('job2')
+    job2.id = 2
+    const job3 = () => calls.push('job3')
+    job3.id = 1
+
+    queueJob(job1)
+    queueJob(job2)
+    queueJob(job3)
+    await nextTick()
+    expect(calls).toEqual(['job3', 'job2', 'job1'])
+  })
 })