Fixed error in order of EventTypeDescriptions -- seq and par GC come after start and finish GC.

EventTypeDescriptions order must be synchronized with the event type
definitions in includes/EventLogFormat.h for the definitions to correctly
index with the matching description.

rts/eventlog/EventLog.c

@@ -45,10 +45,10 @@ char *EventDesc[] = {
   "Steal spark",
   "Shutdown",
   "Wakeup thread",
-  "Request sequential GC",
-  "Request parallel GC",
   "Starting GC",
   "Finished GC",
+  "Request sequential GC",
+  "Request parallel GC",
   "Create spark"
 };