This CL re-implements CopyFromPrototype, that is used during sorting,
as a runtime function, in preparation to move Array.p.sort to CSA.

CopyFromPrototype is called for sparse non-arrays, where elements
might be available on the prototype chain. For compatibility with
JSC, we copy them to the object itself and sort only own properties.

Bug: v8:7382
Change-Id: I4f5c14995cf9769c4f9f1d62b3a5bfde6d386556
Reviewed-on: https://chromium-review.googlesource.com/1044205
Commit-Queue: Simon Zünd <szuend@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53061}