Especially for function types, this increases readability significantly.
Also the style guide recommends for 'using' over 'typedef'.

R=mstarzinger@chromium.org

Bug: v8:9183
Change-Id: If2d17863de39383f5a35e089298d37408791ce4b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1631415
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61872}