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 src/objects to 'using' declarations.

R=mstarzinger@chromium.org

Bug: v8:8834
Change-Id: Iec455b40e9256ee3aae867a42c0e949a338d417c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1545893Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60531}