When we call ObjectToString on JSValues we only looked at string tags
on the prototype map of the JSValue's value type and do not check the
tags on the JSValue's prototype chain which may be non-trivial if
subclassing is involved. For ex: if we have a class Test extend Number,
we only looked for tags on the Number prototype and not on the Test
prototype. This cl fixes the builtin to also check for these cases.


Bug: v8:7706
Change-Id: I9f0e3bb6499646bf27b92bf4fb4e9014f6efa56b
Reviewed-on: https://chromium-review.googlesource.com/c/1378176Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Mythri Alle <mythria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58338}