Problem: ZAP status codes != 200 do not result in an appropriate monitor event (#2665)

* Problem: missing test for status code 300, inadequate assertion for status code 500

Solution: add test, change assertion (currently test fails)

* Problem: gcc compiler error deprecated conversion from string constant

Solution: declare variable as const

* Problem: in case of ZAP handler returning a status code other than 200, no appropriate event is emitted

Solution: immediately emit event after receiving reply from ZAP handler

* Problem: endpoint address is not included in zap-reply monitor event

Solution: added functions to retrieve endpoint address in zmq::i_engine and zmq::session_base_t
removed unused code block in zmq::stream_engine_t::next_handshake_command

* Problem: wrong formatting

Solution: fix formatting

* Problem: test fails because of EPIPE

Solution: add EPIPE/ECONNRESET/ECONNAGAIN handling for more test cases

src/session_base.cpp

@@ -113,6 +113,11 @@ zmq::session_base_t::session_base_t (class io_thread_t *io_thread_,
 {
 }
 
+const char *zmq::session_base_t::get_endpoint () const
+{
+    return engine->get_endpoint ();
+}
+
 zmq::session_base_t::~session_base_t ()
 {
     zmq_assert (!pipe);