This reverts commit d11a0648.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> [torque] Implement safe initialization of classes through hidden structs
> 
> Initialization of classes now happens atomically at the end of the
> class constructor only once all of the values for the class' fields
> have been fully computed. This makes Torque constructors completely
> GC safe, e.g. hardened against allocations or exceptions in
> constructors.
> 
> As part of this change, make the 'this' parameter for method calls
> explicit rather than implicit.
> 
> Drive by: add validation to check for duplicate field declarations
> 
> Bug: v8:7793
> Change-Id: I8b5e85980d6a103ef9fc3262b76f6514f36ebf88
> Reviewed-on: https://chromium-review.googlesource.com/c/1411252
> Commit-Queue: Daniel Clifford <danno@chromium.org>
> Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58979}

TBR=danno@chromium.org,tebbi@chromium.org

Change-Id: Id6c46c175f53c5a77db1e6ca242586fba34cd02e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7793
Reviewed-on: https://chromium-review.googlesource.com/c/1426121Reviewed-by: Daniel Clifford <danno@chromium.org>
Commit-Queue: Daniel Clifford <danno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58980}