Proposal repo: https://github.com/tc39/proposal-symbol-description

Add new Builtin SymbolPrototypeDescriptionGetter.

Bug: v8:7807
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: I7353bd00b172e91d8624e3373d2a4b55aced8b5c
Reviewed-on: https://chromium-review.googlesource.com/1088871
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53592}