tests: add %NOLISTENPORT and use it

The purpose with this variable is to provide a port number that is
reasonably likely to not have a listener on the local host so that tests
can try connect failures against it. It uses port 47 - "reserved"
according to IANA.

Updated six tests to use it instead of the previous different ports.

Assisted-by: Emil Engler
Closes #5270

tests/data/test19

@@ -24,7 +24,7 @@ http
 attempt connect to non-listening socket
  </name>
  <command>
-%HOSTIP:2
+%HOSTIP:%NOLISTENPORT
 </command>
 </client>
 

tests/data/test504

@@ -32,7 +32,7 @@ lib504
 simple multi through local proxy without listener
  </name>
  <command>
-http://%HOSTIP:%HTTPSPORT/504 %HOSTIP:55555
+http://%HOSTIP:%HTTPSPORT/504 %HOSTIP:%NOLISTENPORT
 </command>
 </client>
 

tests/data/test702

@@ -31,7 +31,7 @@ proxy
 Attempt connect to non-listening HTTP server via SOCKS4 proxy
  </name>
  <command>
---socks4 %HOSTIP:%SOCKSPORT http://%HOSTIP:60000
+--socks4 %HOSTIP:%SOCKSPORT http://%HOSTIP:%NOLISTENPORT
 </command>
 </client>
 

tests/data/test703

@@ -31,7 +31,7 @@ proxy
 Attempt connect to non-listening HTTP server via SOCKS5 proxy
  </name>
  <command>
---socks5 %HOSTIP:%SOCKSPORT http://%HOSTIP:60000
+--socks5 %HOSTIP:%SOCKSPORT http://%HOSTIP:%NOLISTENPORT
 </command>
 </client>
 

tests/data/test704

@@ -23,7 +23,7 @@ http
 Attempt connect to non-listening SOCKS4 proxy
  </name>
  <command>
---socks4 %HOSTIP:2 http://%HOSTIP:%HTTPPORT/704
+--socks4 %HOSTIP:%NOLISTENPORT http://%HOSTIP:%HTTPPORT/704
 </command>
 <features>
 proxy

tests/data/test705

@@ -23,7 +23,7 @@ http
 Attempt connect to non-listening SOCKS5 proxy
  </name>
  <command>
---socks5 %HOSTIP:2 http://%HOSTIP:%HTTPPORT/705
+--socks5 %HOSTIP:%NOLISTENPORT http://%HOSTIP:%HTTPPORT/705
 </command>
 <features>
 proxy