OrderedNameDictionarHandler is the external API to interface with the
OrderedNameDictionary variants. This abstracts away the need for the
user to know that there are two different backing stores.

Bug: v8:6443, v8:7569
Change-Id: Ief4f0904823988e629a01060b018b4cb0291542d
Reviewed-on: https://chromium-review.googlesource.com/c/1381758
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58369}