Previously we'd first accumulate errors to the parent and validate the
destructuring pattern in the parent. In the case of ParseArguments this
will invalidly propagate binding pattern errors from one argument to the
next. The reason why ParseArguments keeps track of binding pattern errors
is because it could also be used to parse async arrow function parameters.
If we see async(a,b) we don't yet know whether this is the head of an
async arrow function, or a call to async with arguments a and b.

Bug: v8:8241
Change-Id: I670ab9a9c6f2e0bee399808b02a465ae1afa7c3f
Reviewed-on: https://chromium-review.googlesource.com/c/1296229
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56887}