Revert limiting of fetching, it didn't help perf.

synapse/storage/events.py

@@ -505,15 +505,8 @@ class EventsStore(SQLBaseStore):
         while True:
             try:
                 with self._event_fetch_lock:
-                    tot = 0
-                    j = 0
-                    for j, lst in enumerate(self._event_fetch_list):
-                        if tot > 200:
-                            break
-                        tot += len(lst[0])
-
-                    event_list = self._event_fetch_list[:j+1]
-                    self._event_fetch_list = self._event_fetch_list[j+1:]
+                    event_list = self._event_fetch_list
+                    self._event_fetch_list = []
 
                     if not event_list:
                         if self.database_engine.single_threaded or i > 3: