Unsure why we added this requirement in the past. We shouldn't need
to explicitly specify a ssd dimension for the bots.

Removing to simplify the migration to .star files.

Bug: angleproject:5559
Change-Id: I55484dec74e4274013390d378678824a3ed0778a
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2678865Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>