Cleanup uses of QUIC version

This CL gets us closer to being able to turn ParsedQuicVersion into a class. It does not change any behavior.

No behavior change

PiperOrigin-RevId: 323895265
Change-Id: I940f8ce54e0c62efab485da1140f623a51b245d7

quic/core/quic_buffered_packet_store.cc

diff --git a/quic/core/quic_buffered_packet_store.cc b/quic/core/quic_buffered_packet_store.cc
index cafe871..a90cef6 100644
--- a/quic/core/quic_buffered_packet_store.cc
+++ b/quic/core/quic_buffered_packet_store.cc
@@ -57,7 +57,7 @@
 BufferedPacketList::BufferedPacketList()
     : creation_time(QuicTime::Zero()),
       ietf_quic(false),
-      version(PROTOCOL_UNSUPPORTED, QUIC_VERSION_UNSUPPORTED) {}
+      version(ParsedQuicVersion::Unsupported()) {}
 
 BufferedPacketList::BufferedPacketList(BufferedPacketList&& other) = default;
 
@@ -94,7 +94,7 @@
       << "Shouldn't buffer duplicated CHLO on connection " << connection_id;
   QUIC_BUG_IF(!is_chlo && !alpns.empty())
       << "Shouldn't have an ALPN defined for a non-CHLO packet.";
-  QUIC_BUG_IF(is_chlo && version.transport_version == QUIC_VERSION_UNSUPPORTED)
+  QUIC_BUG_IF(is_chlo && !version.IsKnown())
       << "Should have version for CHLO packet.";
 
   const bool is_first_packet =