sanitycheck builds too many duplicates in CI, make it smarter

Right now we invoke sanitycheck multiple times based on board and sample changes and then the default run, this results in many duplicates.

Create a new mode for sanitycheck were it generates a list of the tests to be run based on options (dry run) and then process all of those lists and generate a unique list that can be fed to sanitycheck to determine what should run for real.