The hardfloat calling convention reserves registers d0 to d7 for passing
double parameters, any parameters after that will be passed on the
stack.

We do not pass more than a couple of double parameters at a time when
calling C functions from generated code in V8, so this hasn't been an
issue but it could be in the future.

Change-Id: I44971ef0943894c201ddb908031ba9cf6fc0bc8e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2507692Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#70985}