Revert 255928 "Only notify V8 once per timezone change"

> Only notify V8 once per timezone change
> 
> The timezone is a global property. No need to notify V8 for every single
> frame.
> 
> As a side-effect, we don't have a race with context creation.
> 
> BUG=348856
> R=marja@chromium.org, kalman@chromium.org
> 
> Review URL: https://codereview.chromium.org/190763008

TBR=jochen@chromium.org

Review URL: https://codereview.chromium.org/190953007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255939 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255939