NEONModifiedImmShiftLsl and NEONModifiedImmShiftMsl will also have a
DCHECK(is_uint8(imm)), however by that time we may have truncated the
uint64_t integer with a static_cast<int>.

Bug: v8:11033
Change-Id: Id0786e6525e385294748af6c77bdee4ca6db106c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2520901Reviewed-by: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#71019}