Even though both are allowed in the style guide, it recommends to use
'using', as its syntax is more consistent with the rest of C++.
This CL turns all typedefs in parsing code to 'using' declarations.

R=leszeks@chromium.org

Bug: v8:8834
Change-Id: I0c95f83ee6897d294bd002b7a4a6277962397e90
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1545897Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60522}