Benchmark suite return code validation

[iondbproject]

The benchmarking suite, ionbench, currently assumes the implementation under test is fully functional. Some checks should be added to assert the return code from the methods tested (such as dictionary_create, dictionary_insert, etc) are returning err_ok, and not something bad like err_out_of_memory.

Possible talking points:

• These checks will cause a small amount of delay, resulting in slightly higher timing measurements. Is this acceptable? Do we adjust for this in any way?
• These checks could be made redundant if we were to deploy solid unit tests on device. Then the behavior of the implementation can be verified before we benchmark.

[Stickerpants]

Issue moved to internal task tracker.