When looking for private members in an object for the inspector,
we check if that object is a class constructor with the a bit
has_static_private_methods set on its SFI. If it
is, we look for any variables in the context locals
with a VariableMode associated with private methods or accessors
and a IsStaticFlag being kStatic.

This patch also filters out static private methods when inspecting
instances.

Design doc: https://docs.google.com/document/d/1N91LObhQexnB0eE7EvGe57HsvNMFX16CaWu-XCTnnmY/edit
See also: https://docs.google.com/document/d/14maU596YbHcWR7XR-_iXM_ANhAAmiuRlJZysM61lqaE/edit

Bug: v8:9839, v8:8330
Change-Id: Idad15349c983898de2ce632c38b0174da10e639d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1955664Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Joyee Cheung <joyee@igalia.com>
Cr-Commit-Position: refs/heads/master@{#66636}