This CL removes the duplicated code for handling global
state of the app. Increases readability of the app
class.

Bug: v8:10673, v8:10644

Change-Id: I08e0bfdc67e023264fce22a96bfd3ef94644e70c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2302894Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Commit-Queue: Zeynep Cankara <zcankara@google.com>
Cr-Commit-Position: refs/heads/master@{#68918}