Tweaks to roll_deps.py.
Tweaks to roll_deps.py.

Removes a few repos that are no longer in DEPS. Also remove fuchsia_sdk
as it's not avaiable by default on some platforms and isn't really part
of Chromium.

Bug: angleproject:4176
Change-Id: I141213811c085b4281f64d93a14eb4a2b83e005e
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1940567
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle