Always use recvmmsg or recvmsg if it's available, and consolidate ReadAndDispatchPackets and ReadAn…

net/tools/quic/quic_server.h

Index: net/tools/quic/quic_server.h
diff --git a/net/tools/quic/quic_server.h b/net/tools/quic/quic_server.h
index 49718dbde6a932e341e82f9a531668b026ec4828..24523ded14fc777c0c9d0e93236ee1c7cdba77da 100644
--- a/net/tools/quic/quic_server.h
+++ b/net/tools/quic/quic_server.h
@@ -113,9 +113,6 @@ class QuicServer : public EpollCallbackInterface {
   // because the socket would otherwise overflow.
   bool overflow_supported_;
 
-  // If true, use recvmmsg for reading.
-  bool use_recvmmsg_;
-
   // config_ contains non-crypto parameters that are negotiated in the crypto
   // handshake.
   QuicConfig config_;