By now we no longer call {CodeStub} targets directly from WebAssembly
code and hence can remove support for serializing and deserializing such
call sites.

R=clemensh@chromium.org

Change-Id: Ibfea9fce178d49f4e739a049a6767031da3c9569
Reviewed-on: https://chromium-review.googlesource.com/1066013
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53299}