Previously the V8 inspector would report native accessors, whose getter
evaluates to a value without causing a side effect, as own data
properties. But then the DevTools front-end will not be able to tell
whether that accessor was actually an own property or just an inherited
accessor.

The reason for reporting them as own properties in the first place was
to ensure that these properties show up in the object's preview. But
that we can handle differently by just marking these properties as
synthetic internally and including them in the preview.

Bug: chromium:1076820
Change-Id: I223299af7954e7b1a4a16bb5180d4ceff50f170f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3094005
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Kim-Anh Tran <kimanh@chromium.org>
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Kim-Anh Tran <kimanh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76276}