Port 4b3371c6

Original Message:
  This will make it easier to generate builtin calls that require the
  context to be passed in that register, because this can be represented
  as a {LiftoffRegister} then.

Change-Id: I35f14d9f5460706ef1d51f39a7eb3afdf0979f9d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2764682Reviewed-by: Milad Fa <mfarazma@redhat.com>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/master@{#73543}