atk key: Always convert control character events into key names

including when the control modifier is present, i.e. when one is typing
control-I for instance.

Orca would convert them back to the corresponding ASCII letter anyway, and
when pressing control-tab, we do want to pass "tab", not pass "\t" that Orca
would erroneously convert to "control-I".

Fixes #1743

gtk/a11y/gtkaccessibilityutil.c

@@ -123,8 +123,7 @@ atk_key_event_from_gdk_event_key (GdkEventKey       *key,
   event->keyval = key->keyval;
   event->length = key->length;
   if (key->string && key->string[0] &&
-      (key->state & GDK_CONTROL_MASK ||
-       g_unichar_isgraph (g_utf8_get_char (key->string))))
+      g_unichar_isgraph (g_utf8_get_char (key->string)))
     event->string = key->string;
   else
     event->string = gdk_keyval_name (key->keyval);