Move the sleep function to jerry-port (#2245)

Now the jerry-debugger uses the jerry-port's sleep, therefore if there are systems that don't support
usleep or nanosleep can now define their own function.

JerryScript-DCO-1.0-Signed-off-by: Istvan Miklos imiklos2@inf.u-szeged.hu

jerry-core/include/jerryscript-port.h

@@ -138,6 +138,13 @@ double jerry_port_get_current_time (void);
  */
 struct jerry_instance_t *jerry_port_get_current_instance (void);
 
+/**
+ * Makes the process sleep for a given time.
+ */
+#ifdef JERRY_DEBUGGER
+void jerry_port_sleep (uint32_t sleep_time);
+#endif /* JERRY_DEBUGGER */
+
 /**
  * @}
  */