Knowing the boundary of each subtest can be instrumental in digesting
the voluminous trace output and finding the critical piece of
information.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180713203529.1973-1-chris@chris-wilson.co.uk