emulation on host: missing mock functions, improve host interface handling (#7404)

Author: d-a-v

tests/host/common/MockEsp.cpp

@@ -108,6 +108,11 @@ uint32_t EspClass::getFreeHeap()
 	return 30000;
 }
 
+uint16_t EspClass::getMaxFreeBlockSize()
+{
+	return 20000;
+}
+
 String EspClass::getResetReason()
 {
   return "Power on";

tests/host/common/MockWiFiServerSocket.cpp

@@ -145,3 +145,8 @@ void WiFiServer::close ()
 		::close(pcb2int(_listen_pcb));
 	_listen_pcb = int2pcb(-1);
 }
+
+void WiFiServer::stop ()
+{
+    close();
+}