benchtests: Adjust valid and accepted properties

benchtests: Adjust valid and accepted properties

Benchmark workload-spec2006.wrf does not produce max, min or mean
results but instead produce throughput. This is represented in
benchtests/bench-skeleton.c. This patch adjust benchout.schema.json to consider
bench.out from bench-math benchmarks as valid

ChangeLog:

	* benchtests/scripts/benchout.schema.json: Add throughput as accepted
	result from property and remove "max", min" and "mean" from required
	properties based on benchtests/bench-skeleton.c.

Signed-off-by: Victor Rodriguez <victor.rodriguez.bahena@intel.com>
Reviewed-By: Siddhesh Poyarekar <siddhesh@sourceware.org>