For import wrappers, we add a special "callable" parameter as the last
parameter. This parameter is not set in the TurboFan graph but in the
code generator. Therefore this parameter has to be allocated in a
special register and cannot be lowered generically. With this CL we
detect in the CallDescriptor lowering if the last parameter is this
special "callable" parameter. If so, we preserve it in the lowered
CallDescriptor in the same register.

R=jkummerow@chromium.org

Bug: v8:7741
Change-Id: I884baa41813011c811612ec84f4e3cfe86a0e83a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1762014Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63344}