bug#32198: tail -f -F unexpected behavior

[Matthew Guidry]

This is for tail v8.28 encountered on Ubuntu 18.04.

I was doing some experimentation with nano v2.9.3 and tail,
watching the output of tail after saving in nano and encountered some
strange behavior.

I had two terminals open side by side; one with nano and one with tail.
I opened a file called test.txt in nano and saved with ^w in the first
terminal.
I went to the second terminal and ran tail -f test.txt to watch the file.

I went back to the nano terminal and returned twice and saved.
The tail terminal reports this change properly.
With the file still open in nano, I write any number of characters and save.

The tail terminal reports this change But skips the first character. I also
tested this with -F.

This may not be an issue because it only happens when using the
write(ctrl-o, ctrl-s) in nano and not closing the file.

I have reproduced this on two machines.