lib/tinytest: Clean up test reporting in the presence of stdout output.

tinytest is written with the idea that tests won't write to stdout, so it
prints test name witjout newline, then executes test, then writes status.
But MicroPython tests write to stdout, so the test output becomes a mess.
So, instead print it like:

    # starting basics/andor.py
    ... test output ...
    basics/andor.py: OK

0 files changed, 0 insertions, 0 deletions