add EEMBC Coremark test

Created by: strichmo

Task Outcome

The coremark suite is a general purpose processor benchmark and the below link is EEMBC's MCU version of it. Similar to EMBench we should have a version of this running our the 40X and 40S with performance tracking.

https://github.com/eembc/coremark

Completion Criteria

The benchmark executes on the 40X