drm/i915/selftests: Check for engine-reset errors in the middle of workarounds

As we reset the engine between verifying the workarounds remain intact,
report an engine reset failure.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210125140136.10494-1-chris@chris-wilson.co.uk


Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>