The motivation behind this change is that the WasmArgumentsAdaptor
builtin needed too many registers on ia32 and was blocking work on
adding a root register.

Bug: v8:6666
Change-Id: I9d39af96e8520acc092f5ef4b7f0a159fe4e3b12
Reviewed-on: https://chromium-review.googlesource.com/1209788
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55761}