all: Remove tinytest component.

With the recent qemu (d9a0fdda9a and
0426934969) and zephyr
(05cad7b56f) changes to how their tests are
run, two things became unused:

- The tinytest framework, which embedded a set of tests and their expected
  output within firmware, so these tests could be run stand-alone.

- The `--write-exp` and `--list-tests` options to `tests/run-tests.py`,
  which were needed primarily to generated the expected test output for
  tinytest (also the associated `tests/run-tests-exp.py/.sh` scripts are
  now unused).

This commit removes the tinytest component and all its helper code.  This
eliminates a maintenance burden.

Signed-off-by: Damien George <damien@micropython.org>

LICENSE

@@ -59,7 +59,6 @@ used during the build process and is not part of the compiled source code.
         /pico-sdk (BSD-3-clause)
         /re15 (BSD-3-clause)
         /stm32lib (BSD-3-clause)
-        /tinytest (BSD-3-clause)
         /tinyusb (MIT)
         /uzlib (Zlib)
         /wiznet5k (MIT)