graphics_GLMark2: make it work on freon

On freon, don't quit without doing anything.
Stop/start X server only if not freon.
Also look for an executable named glmark2-waffle.

BUG=chromium:413081
TEST=test_that -b link -i trybot-link-paladin/R45-7133.0.0-b1984 :lab: graphics_GLMark2
CQ-DEPEND=CL:274548

Change-Id: Icbd66a09ca2b736af871dbb72fd0fae2e082975e
Reviewed-on: https://chromium-review.googlesource.com/274711
Reviewed-by: Ilja Friedel <ihf@chromium.org>
Reviewed-by: Frank Henigman <fjhenigman@chromium.org>
Commit-Queue: Frank Henigman <fjhenigman@chromium.org>
Tested-by: Frank Henigman <fjhenigman@chromium.org>
2 files changed