This adds the Python files in the tests/ directory to be formatted with
./tools/codeformat.py. The basics/ subdirectory is excluded for now so we
aren't changing too much at once.
In a few places `# fmt: off`/`# fmt: on` was used where the code had
special formatting for readability or where the test was actually testing
the specific formatting.
These tests are intended to fail, as they provide a programatic record of
differences between uPy and CPython. They also contain a special comment
at the start of the file which has meta-data describing the difference,
including known causes and known workarounds.
