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/extmod/vfs_blockdev.py

@@ -2,12 +2,14 @@
 
 try:
     import uos
+
     uos.VfsFat
     uos.VfsLfs2
 except (ImportError, AttributeError):
     print("SKIP")
     raise SystemExit
 
+
 class RAMBlockDevice:
     ERASE_BLOCK_SIZE = 512
 
@@ -28,15 +30,16 @@ class RAMBlockDevice:
             self.data[addr + i] = buf[i]
 
     def ioctl(self, op, arg):
-        if op == 4: # block count
+        if op == 4:  # block count
             return len(self.data) // self.ERASE_BLOCK_SIZE
-        if op == 5: # block size
+        if op == 5:  # block size
             return self.ERASE_BLOCK_SIZE
-        if op == 6: # erase block
+        if op == 6:  # erase block
             return 0
 
+
 def test(bdev, vfs_class):
-    print('test', vfs_class)
+    print("test", vfs_class)
 
     # mkfs
     vfs_class.mkfs(bdev)
@@ -45,21 +48,22 @@ def test(bdev, vfs_class):
     vfs = vfs_class(bdev)
 
     # statvfs
-    print(vfs.statvfs('/'))
+    print(vfs.statvfs("/"))
 
     # open, write close
-    f = vfs.open('test', 'w')
+    f = vfs.open("test", "w")
     for i in range(10):
-        f.write('some data')
+        f.write("some data")
     f.close()
 
     # ilistdir
     print(list(vfs.ilistdir()))
 
     # read
-    with vfs.open('test', 'r') as f:
+    with vfs.open("test", "r") as f:
         print(f.read())
 
+
 try:
     bdev = RAMBlockDevice(50)
 except MemoryError: