Implement software bus bulk transfer functional test

[jphickey]

Is your feature request related to a problem? Please describe.
Requests have been received to include software bus performance as part of the test matrix.

Describe the solution you'd like
Start by implementing a functional test case (as part of cfe_testcase) that emulates using the software bus for bulk message transfer, by sending a fixed large number of messages (e.g. 1 million). This process can be timed, and this in turn will give some indication of relative performance of the implementation.

Additional context
This obviously could be much more sophisticated. The proposed test only covers the simplest case, in single thread/single core context, and the results are only comparable to successive runs on the exact same hardware with the same compiler and same compiler flags. Nonetheless, monitoring the result before and after a change will provide at least one simple metric of whether that change affects performance or not.

A follow-on change should perform a similar test with multiple threads, and thus give some metrics to how well SB scales across cores.

Requester Info
Joseph Hickey, Vantage Systems, Inc.