This reverts commit 79b00555.

Reason for revert: needs more discussion

Original change's description:
> [torque] introduce JSAny type for user-accessible JavaScript values
> 
> This CL introduces a JSAny type for user-exposed JavaScript values and
> a few new types to define it. Especially, it splits Symbol into
> PrivateSymbol (not exposed) and PublicSymbol (JavaScript exposed
> symbols).
> 
> The change is mostly mechanical, but a few things are interesting:
> - PropertyKey and JSPrimitive were designed to coincide with the spec
>   notions of IsPropertyKey() and primitive value, respectively.
> - Since Name is an open type, we define AnyName to be the known
>   subtypes of Name. This is not too elegant, but by using AnyName
>   instead of Name, typeswitch can properly conclude something if a
>   subtype of Name is excluded.
> 
> Small drive-by changes, which were necessary:
> - Allow subtyping on label parameters.
> - Fix the formatting of typeswitch, it was broken with union types
>   in case types.
> 
> Bug: v8:7793
> Change-Id: I14b10507f8cf316ad85e048fe8d53d1df5e0bb13
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1735322
> Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63114}

TBR=neis@chromium.org,jgruber@chromium.org,tebbi@chromium.org

Change-Id: Ifde7881d74afe407628f40047997339d54cb2424
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:7793
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1741652Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63115}