[liftoff] Push the instance as part of frame construction

Currently we first construct the frame (via
{TurboAssembler::EnterFrame}), then we spill the instance to the
respective slot (via {LiftoffAssembler::SpillInstance}). Instead, we
should already spill the instance as part of frame construction. That
allows for a more compact instruction to be used ("push" instead of
"mov" on Intel), and on arm64 even allows to merge pushing into an
existing instruction (where we currently push the zero register x31
instead).

This makes the prologue more similar to what TurboFan generates in
{TurboAssembler::AssembleConstructFrame} (which does not use
{TurboAssembler::EnterFrame}).

R=ahaas@chromium.org

Bug: v8:12017
Change-Id: Ibb4a38d2049cff66fec9450db4f7f375d006beac
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3055302


Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75938}