This reverts commit 6f9b2bd4.

Reason for revert: Fails on nvidia bots, blocking LKGR: https://ci.chromium.org/p/v8/builders/ci/Win%20V8%20FYI%20Release%20(NVIDIA)/5005

Original change's description:
> [ptr-compr] Make on-heap JSTypedArrays smi-corrupting friendly
> 
> On-heap typed arrays contain HeapObject value in |base_pointer| field
> and an offset in |external_pointer| field. When pointer compression is
> enabled we want to combine decompression with the offset addition.
> In order to do that we add an isolate root to the external_pointer value
> and therefore the data pointer computation can is a simple addition of
> a (potentially sign-extended) |base_pointer| loaded as Tagged_t value
> and an |external_pointer| value.
> 
> Bug: v8:9706
> Change-Id: Id5c546c353c81fb25e3598921bc78165d10a9c44
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1807369
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Reviewed-by: Georg Neis <neis@chromium.org>
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63874}

TBR=ulan@chromium.org,neis@chromium.org,jgruber@chromium.org,ishell@chromium.org,verwaest@chromium.org

Change-Id: I901280dd191e78d02969600f775c4f0da796921f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:9706
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1813027Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63886}