Test Macro Functionality

[IshDeshpa]

Whenever we compile our code to run a test file, we need to define some sort of global TEST macro that will allow us to condition on whether we are testing or not. An example of this in our current codebase is __TEST_SendTritium in SendTritium.h, but I'd like a more global TEST macro that will apply to all of our codebase. This macro will enable any conditional code in our BSP/drivers/apps that we only want to run/access when testing.

[IshDeshpa]

This may need to be reevaluated based on larger design decisions and our needs under the new software architecture. Do we want one test macro or multiple (one for each file)? Do we even want any sort of conditional test functionality in our source code, or should it be relegated to test files only? More consideration needs to be made.

[IshDeshpa]

Closing this in favor of #378