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These trybots will go into the general luci.chromium.try bucket. Right
now only the Linux and Mac ones have been set up, but it's harmless to
register all of them now. (The optional GPU tryservers are already in
this console and conversion has only just started for them.)

Also added a separate angle.try console with just these LUCI trybots.

Bug: 815092
Change-Id: I27d04c7a2b7ef5cf773eb96427e09e8552647640
Reviewed-on: https://chromium-review.googlesource.com/955560
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Nodir Turakulov <nodir@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541978}