bpo-37150: Throw ValueError if FileType class object was passed in add_argument ...

bpo-37150: Throw ValueError if FileType class object was passed in add_argument (GH-13805)

There is a possibility that someone (like me) accidentally will omit parentheses with `FileType` arguments after `FileType`, and parser will contain wrong file until someone will try to use it.

Example:
```python
parser = argparse.ArgumentParser()
parser.add_argument('-x', type=argparse.FileType)
```

https://bugs.python.org/issue37150
(cherry picked from commit 03d5831a2d62c68654ec223168e574cd546efbf6)

Co-authored-by: zygocephalus <grrrr@protonmail.com>