This removes the check for holeyness when using CopyFixedArrayElements,
because the function does not use that information.

Change-Id: I6033495bf00947ded083ebc24695f6c8bf4569d0
Reviewed-on: https://chromium-review.googlesource.com/c/1280763
Commit-Queue: Hai Dang <dhai@google.com>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56646}