Disable piglit in the test lab.

With every Intel board except for generic on Freon there is no need to
schedule Piglit anymore. It will be replaced by dEQP.

BUG=chromium:413082
TEST=None.

Change-Id: I5bd149bd516a724ddacf5afb5efea4cc55751d2c
Reviewed-on: https://chromium-review.googlesource.com/295931
Commit-Ready: Ilja Friedel <ihf@chromium.org>
Tested-by: Ilja Friedel <ihf@chromium.org>
Reviewed-by: Haixia Shi <hshi@chromium.org>
22 files changed