analyzer: fix ICE on 'bind(INT_CST, ...)' [PR107783]
This was crashing inside fd_phase_mismatch's ctor with assertion
failure when the state was "fd-constant".
Fix the ICE by not complaining about constants passed to these APIs.
gcc/analyzer/ChangeLog:
PR analyzer/107783
* sm-fd.cc (fd_state_machine::check_for_new_socket_fd): Don't
complain when old state is "fd-constant".
(fd_state_machine::on_listen): Likewise.
(fd_state_machine::on_accept): Likewise.