condition memory test to ESP boards and add define to the test config

#173

tests/Test_config.h

@@ -168,5 +168,6 @@ const byte subnet[] = { 255, 255, 255, 0 }; //ip adress
 //variables to avoid duplicates
 #define time_avoid_duplicate 3000 // if you want to avoid duplicate mqtt message received set this to > 0, the value is the time in milliseconds during which we don't publish duplicates
 
+#define TimeBetweenReadingSYS 30000 // time between system readings (like memory)
 /*-------------------ACTIVATE TRACES----------------------*/
 #define TRACE 1  // 0= trace off 1 = trace on