message: refactor: reduce component mergeHook arg count
  Because removed the two extra args from init hook
diff: @@ -236,9 +236,9 @@ function installComponentHooks (data: VNodeData) {
  }
  function mergeHook (f1, f2) {
  - const merged = (a, b, c, d) => {
  - f1(a, b, c, d)
  - f2(a, b, c, d)
  + const merged = (a, b) => {
  + f1(a, b)
  + f2(a, b)
  }
  merged._merged = true
  return merged
  