[TD-2986]<test>: add demo example into CI

tests/examples/c/demo.c

@@ -66,7 +66,7 @@ int main(int argc, char *argv[]) {
     printf("failed to connect to server, reason:%s\n", "null taos"/*taos_errstr(taos)*/);
     exit(1);
   }
-  for (int i = 0; i < 4000000; i++) {
+  for (int i = 0; i < 100; i++) {
     Test(taos, qstr, i);
   }
   taos_close(taos);

tests/test-all.sh

@@ -517,6 +517,15 @@ if [ "$2" != "sim" ] && [ "$2" != "python" ] && [ "$2" != "jdbc" ] && [ "$2" !=
     totalExamplePass=`expr $totalExamplePass + 1`
   fi
 
+  ./demo 127.0.0.1 > /dev/null 2>&1
+  if [ $? != "0" ]; then
+    echo "demo failed"
+    totalExampleFailed=`expr $totalExampleFailed + 1`    
+  else
+    echo "demo pass"
+    totalExamplePass=`expr $totalExamplePass + 1`
+  fi
+  
   if [ "$totalExamplePass" -gt "0" ]; then
     echo -e "\n${GREEN} ### Total $totalExamplePass examples succeed! ### ${NC}"
   fi