[test] System-Level Tests for the C API Should Have a Richer CLI

[ppenna]

Context

System-level tests for the C API miss a rich command line interface.

For instance, in the push-pop tests, we the maximum number of iterations are hard code as compile-time constants, similarly for the maximum number of bytes to transfer in ping-pong tests.

Proposed Solution

• [ ] In push-pop tests, the DATA_SIZE and MAX_ITERATIONS constants should be overridable by command line arguments.
• [ ] In ping-pong tests, the DATA_SIZE and MAX_BYTES constants should be overridable by command line arguments.