core: types: less allocations when hashing and tx handling (#21265)

* core, crypto: various allocation savings regarding tx handling

* core: reduce allocs for gas price comparison

This change reduces the allocations needed for comparing different transactions to each other.
A call to `tx.GasPrice()` copies the gas price as it has to be safe against modifications and
also needs to be threadsafe. For comparing and ordering different transactions we don't need
these guarantees

* core: added tx.GasPriceIntCmp for comparison without allocation

adds a method to remove unneeded allocation in comparison to tx.gasPrice

* core/types: pool legacykeccak256 objects in rlpHash

rlpHash is by far the most used function in core that allocates a legacyKeccak256 object on each call.
Since it is so widely used it makes sense to add pooling here so we relieve the GC.
On my machine these changes result in > 100 MILLION less allocations and > 30 GB less allocated memory.

* reverted some changes

* reverted some changes

* trie: use crypto.KeccakState instead of replicating code

Co-authored-by: Martin Holst Swende <martin@swende.se>

core/tx_list_test.go

@@ -17,6 +17,7 @@
 package core
 
 import (
+	"math/big"
 	"math/rand"
 	"testing"
 
@@ -49,3 +50,21 @@ func TestStrictTxListAdd(t *testing.T) {
 		}
 	}
 }
+
+func BenchmarkTxListAdd(t *testing.B) {
+	// Generate a list of transactions to insert
+	key, _ := crypto.GenerateKey()
+
+	txs := make(types.Transactions, 100000)
+	for i := 0; i < len(txs); i++ {
+		txs[i] = transaction(uint64(i), 0, key)
+	}
+	// Insert the transactions in a random order
+	list := newTxList(true)
+	priceLimit := big.NewInt(int64(DefaultTxPoolConfig.PriceLimit))
+	t.ResetTimer()
+	for _, v := range rand.Perm(len(txs)) {
+		list.Add(txs[v], DefaultTxPoolConfig.PriceBump)
+		list.Filter(priceLimit, DefaultTxPoolConfig.PriceBump)
+	}
+}