spellcheck.c: add another selftest for PR c/82967

This adds another testcase for overzealous spellchecker suggestions,
reported on IRC.

gcc/ChangeLog:
	PR c/82967
	* spellcheck.c (selftest::test_suggestions): Add another
	assertion.

From-SVN: r266798

gcc/ChangeLog

+2018-12-04  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c/82967
+	* spellcheck.c (selftest::test_suggestions): Add another
+	assertion.
+
 2018-12-04  Martin Sebor  <msebor@redhat.com>
 
 	* doc/extend.texi (__builtin_has_attribute): Fix typo.

gcc/spellcheck.c

@@ -378,6 +378,9 @@ test_suggestions ()
 
   ASSERT_NOT_SUGGESTED_FOR ("__DATE__", "__i386__");
   // dist == 4, max_length == min_length == 8
+
+  ASSERT_NOT_SUGGESTED_FOR ("start_input_device", "InputDevice");
+  // dist == 9, max_length == 18, min_length == 11
 }
 
 /* Verify that find_closest_string is sane.  */