This is a reland of 4b86fea5 with
copy&paste typo in CodeStubAssembler::AllocateByteArray() fixed
(bug led to holes in new space, which was crashing reproducibly
on the ia32 bot).

Original change's description:
> [typedarray] Move external/data pointer to JSTypedArray.
>
> As the next step in supporting huge typed arrays in V8, this moves the
> external/data pointer from the FixedTypedArrayBase backing store to the
> JSTypedArray instance itself, and replaces the special backing stores
> with a plain ByteArray (removing all the code for the FixedTypedArrayBase
> class hierarchy). By doing so, we can drastically simplify the system
> around typed arrays.
>
> Note: Several places in the code base used to check the instance type
> of the elements backing store of a JSTypedArray instead of checking the
> elements kind on the JSTypedArray map directly. Those had to be fixed,
> since the backing store is now always a ByteArray.
>
> Drive-by-fix: Move all the typed elements access related code into the
> elements.cc file to properly encapsulate the accesses.
>
> Doc: http://doc/1Z-wM2qwvAuxH46e9ivtkYvKzzwYZg8ymm0x0wJaomow
> Bug: chromium:951196, chromium:965583, v8:4153, v8:7881, v8:9183
> Change-Id: I8cc06b190c53e34155000b4560f5f3ef40621646
> Cq-Include-Trybots: luci.chromium.try:linux-rel,win7-rel
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1627535
> Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Peter Marshall <petermarshall@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Simon Zünd <szuend@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#61855}

Tbr: petermarshall@chromium.org
Bug: chromium:951196, chromium:965583, v8:4153, v8:7881, v8:9183
Change-Id: I87fcdb28532c5f08cc227332a4d59546cb423810
Cq-Include-Trybots: luci.chromium.try:linux-rel, win7-rel
Cq-Include-Trybots: luci.v8.try:v8_linux_shared_compile_rel
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1631592Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61864}