tests: Format all Python code with black, except tests in basics subdir.

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.

tests/net_hosted/ssl_getpeercert.py

@@ -18,4 +18,4 @@ def test(peer_addr):
 
 
 if __name__ == "__main__":
-    test(socket.getaddrinfo('micropython.org', 443)[0][-1])
+    test(socket.getaddrinfo("micropython.org", 443)[0][-1])