gh-154394: Skip test_tcsendbreak on OpenBSD (GH-154397)

tcsendbreak() is not supported for pseudo-terminals on OpenBSD.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: serhiy-storchaka

Lib/test/test_termios.py

@@ -117,7 +117,7 @@ def test_tcsetattr_errors(self):
     @support.skip_android_selinux('tcsendbreak')
     def test_tcsendbreak(self):
         with skip_enotty_error(self, 'tcsendbreak',
-                               ('freebsd', 'netbsd', 'cygwin')):
+                               ('freebsd', 'netbsd', 'openbsd', 'cygwin')):
             termios.tcsendbreak(self.fd, 1)
             termios.tcsendbreak(self.stream, 1)