core: set max tx size down to 2 slots (64KB)

core/tx_pool.go

@@ -49,7 +49,7 @@ const (
 	// non-trivial consequences: larger transactions are significantly harder and
 	// more expensive to propagate; larger transactions also take more resources
 	// to validate whether they fit into the pool or not.
-	txMaxSize = 4 * txSlotSize // 128KB, don't bump without chunking support
+	txMaxSize = 2 * txSlotSize // 64KB, don't bump without EIP-2464 support
 )
 
 var (