[autotest] Run performance suite on dedicated performance pool

pool:performance is dedicated to run performance test. For a given board, all
duts in pool:performance should have the same SKU.

Also fixed a minor bug in suite_scheduler.ini

BUG=None
TEST=None

Change-Id: I9f920563939adbd577d9056f45c460718b6000d9
Reviewed-on: https://chromium-review.googlesource.com/244120
Commit-Queue: Dan Shi <dshi@chromium.org>
Trybot-Ready: Dan Shi <dshi@chromium.org>
Tested-by: Dan Shi <dshi@chromium.org>
Reviewed-by: Bindu Mahadev <bmahadev@chromium.org>
Reviewed-by: Keith Haddow <haddowk@chromium.org>
1 file changed