Otherwise we'll invalidly propagate information from default function parameters outwards to outer arrow scopes.

Bug: chromium:1060023
Change-Id: Id43ecb5e1d354d5250a80c2a4f7e3129759041d5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2134006
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66964}