[Suggestion] Add original test line to the test output for easier debugging

[TalSk]

So obviously it is extremely hard to debug long tests since you can't know exactly where you failed.
I tried to play with some changes, and figured the following does a decent job (A change to line 84):

    for line_number, line in enumerate(i.readlines()):
        time.sleep(0.1)
        p.stdin.writelines([bytes("printf \"\\nTest line: " + str(line_number) + "\\n\"\n", "utf-8")])

The trick is sending smash an echo command that will print the current test line number. This will require re-running all tests to get the new .exp files.
This is not perfect mainly because it really clutters the output, but it did help me find where I failed way more easily than I would have otherwise.
What do you think?