termios: Fix type of tcgetattr and tcsetattr attributes

[cebtenzzre]

Returning a union from tcgetattr forces the caller to use isinstance or
a type: ignore comment if they modify the returned list. Return
List[Any] instead.

The cc field has ints at cc[termios.VTIME] and cc[termios.VMIN] if
lflag & termios.ICANON is zero. Change _Attr to allow this.

Fixes #4661

The goal is to avoid false positives like this:

example.py:6: error: Unsupported operand types for & ("List[bytes]" and "int")  [operator]
        new[3] = new[3] & ~termios.ECHO          # lflags
                 ^
example.py:6: note: Left operand is of type "Union[int, List[bytes]]"
example.py:7: error: Unsupported target for indexed assignment ("Union[int, List[bytes]]")  [index]
        new[6][termios.VMIN] = 0
        ^
example.py:7: error: No overload variant of "__setitem__" of "list" matches argument types "int", "int"  [call-overload]
        new[6][termios.VMIN] = 0
        ^
example.py:7: note: Possible overload variants:
example.py:7: note:     def __setitem__(self, int, bytes) -> None
example.py:7: note:     def __setitem__(self, slice, Iterable[bytes]) -> None
Found 3 errors in 1 file (checked 1 source file)

[hauntsaninja]

Thanks again!