On x64, reference types where not handled yet in LiftoffAssembler::push.
Note that the values pushed on the stack there do not have to be
handled by a safepoint. The reason is that stack parameters in general
are handled separately from safepoints.

R=thibaudm@chromium.org

Bug: chromium:1168116
Change-Id: Ie62479c13839f0ba240d0e41fa76d07a2cc48881
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2642263Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72252}