This pair, gem_exec_nop/{series,parallel}, are very light stress tests
of which we already perform the same sequence inside
i915_selftests/live_requests. We keep basic uABI coverage (i.e. plain
old gem_execbuf) via the likes of gem_exec_basic and gem_exec_reloc so
all gem_exec_nop adds are nefarious HW details, much less likely to spot
if a test is of sound quality for further testing (and again, we have
alternate coverage of the same HW stress).

Between the pair of subtests, gem_exec_nop takes about 20s of BAT.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Petri Latvala <petri.latvala@intel.com>
Cc: Tomi Sarvela <tomi.p.sarvela@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Acked-by: Petri Latvala <petri.latvala@intel.com>