Roll Fuchsia SDK from 0.20201206.2.1 to 0.20201206.3.1

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/fuchsia-sdk-chromium-autoroll
Please CC chrome-fuchsia-gardener@grotations.appspotmail.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/master/autoroll/README.md

Cq-Include-Trybots: luci.chromium.try:fuchsia-arm64-cast;luci.chromium.try:fuchsia-deterministic-dbg;luci.chromium.try:fuchsia-x64-cast
Tbr: chrome-fuchsia-gardener@grotations.appspotmail.com
Change-Id: I3fcc4dde8a9c5ee41d5831024ab28912afe9bd13
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2576851
Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#834138}