Often at the d8 prompt, you'd like to explore some pointer found
from calls to %DebugPrint(). %DebugPrintPtr() takes a pointer and
attempts to print it as an object.

Change-Id: Ibc3368136a2ed92f400b52dbf2855f3c7d80d887
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2276046Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68617}