Only expect <eof> on non-PyPy implementations.

I have previously encountered similar issues when sending ^C
rather than ^D when the terminal should be in raw_mode with
PyPy:

https://github.com/jquast/blessed/blob/213c3a52a8f64ae147f4cb240a85a7f789bfff5d/blessed/tests/test_keyboard.py#L430-L432

tests/test_interact.py

@@ -66,7 +66,8 @@ def test_interact_escape_None(self):
         p.sendline('')
         p.expect('<out>\x1d')
         p.sendcontrol('d')
-        p.expect('<eof>')
+        if platform.python_implementation() != 'PyPy':
+            p.expect('<eof>')
         p.expect_exact('Escaped interact')
         p.expect(pexpect.EOF)
         assert not p.isalive()