This reverts commit 3411e7c3.

Reason for revert: Breaks test expecations - https://ci.chromium.org/p/chromium/builders/luci.chromium.try/linux_chromium_rel_ng/260731

Original change's description:
> [parser] Create arrow function scopes while parsing the head
> 
> This simplifies NextArrowFunctionInfo, allows us to Scope::Snapshot::Reparent
> directly rather than moving it, and allows us to skip reparenting in the simple
> parameter arrow function cases.
> 
> This CL additionally fixes arrow function name inferring.
> 
> Change-Id: Ie3e5ea778f3d7b84b2a10d4f4ff73931cfc9384a
> Reviewed-on: https://chromium-review.googlesource.com/c/1386147
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Commit-Queue: Toon Verwaest <verwaest@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#58405}

TBR=ishell@chromium.org,verwaest@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I8f31b96f844f0673364bf435fa6c809e40d62fa3
Reviewed-on: https://chromium-review.googlesource.com/c/1388541Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58446}