scripted-diff: Use DataStream in most places

The remaining places are handled easier outside a scripted-diff.

-BEGIN VERIFY SCRIPT-
 sed --regexp-extended -i 's/CDataStream ([0-9a-zA-Z_]+)\(SER_[A-Z]+, [A-Z_]+_VERSION\);/DataStream \1{};/g' $( git grep -l CDataStream)
 sed -i 's/, CDataStream/, DataStream/g' src/wallet/walletdb.cpp
-END VERIFY SCRIPT-

src/test/net_tests.cpp

@@ -1126,7 +1126,7 @@ public:
     void SendV1Version(const MessageStartChars& magic)
     {
         CMessageHeader hdr(magic, "version", 126 + InsecureRandRange(11));
-        CDataStream ser(SER_NETWORK, CLIENT_VERSION);
+        DataStream ser{};
         ser << hdr;
         m_to_send.insert(m_to_send.end(), UCharCast(ser.data()), UCharCast(ser.data() + ser.size()));
     }