Enable CI tests using the Standard Test Interface
    
    Adding initial set of basic functionality tests for mksh
    according to the Standard Test Interface [1]. See Quick Start
    Guide [2] for brief introduction about how to run these tests
    and the Fedora CI portal [3] for more detailed info and links.
    
    [1] https://fedoraproject.org/wiki/CI/Standard_Test_Interface
    [2] https://fedoraproject.org/wiki/CI/Quick_Start_Guide
    [3] https://fedoraproject.org/wiki/CI