If index > JSObject::kMaxElementIndex, we have to perform a prototype
chain lookup for a named property. The corresponding check was missing
for string receivers.

Fixed: chromium:1265043
Change-Id: Ibccd058a4bd108eeee235762bea0bc4163aaa0b3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3257704
Auto-Submit: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77683}