This reverts commit 20727725.

Reason for revert: Many bugs/crashes, https://crbug.com/v8/9999 https://crbug.com/1026500 https://crbug.com/1026514

Original change's description:
> [liftoff] Use stack slot offsets instead of indices
> 
> Spill/fill now take offsets instead of indices. We provide a
> helper, GetStackOffsetFromIndex, for callers. This is currently only
> useful while slot sizes are still fixed to 8 bytes.
> 
> StackTransferRecipe's RegisterLoad now works in terms of offset.
> 
> LiftoffStackSlots work in terms of offset as well.
> 
> TransferStackSlot currently still works in terms of indicies, but can be
> converted to use offsets in a subsequent change.
> 
> Bug: v8:9909
> Change-Id: If54fb844309bdfd641720d063135dd59551813e0
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1922489
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Commit-Queue: Zhi An Ng <zhin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#65049}

TBR=clemensb@chromium.org,zhin@chromium.org

Change-Id: I972b72346c87d1d55488911938e3f3cdbe69abe5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:9909
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1925560Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65080}