Run snapshot_unittests on all desktop bots.

Adds snapshot_unittests to the main waterfall win bots,
the cros memory bots (already running on the others),
and the clang tot bots (all desktop platforms).

Disables the test on Win10, since it doesn't pass there.

Bug: 843511,850556,438897
Change-Id: Ifa577c3fe97bb10544addcd12e69a29a65cff01d
Reviewed-on: https://chromium-review.googlesource.com/1089655
Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#566825}
6 files changed