[tools] Add basic pointer compression to grokdump

Distinguish between tagged and machine pointer sizes in grokdump, and
dump a tagged memory view in addition to the machine-word dump when they
don't match.

This tagged view tries to decompress pointers for link targets, by
masking the slot they're in to get the cage root.

Drive-by: Add a .style.yapf to opt in to python formatting using
git cl format.

Change-Id: Ic5272cd865f995fc670ab2fb7d5e464f317af1bf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3439906Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78948}

.style.yapf

+[style]
+based_on_style = chromium