common/prque: generic priority queue (#26290)

* common, core, eth, les, trie: make prque generic

* les/vflux/server: fixed issues in priorityPool

* common, core, eth, les, trie: make priority also generic in prque

* les/flowcontrol: add test case for priority accumulator overflow

* les/flowcontrol: avoid priority value overflow

* common/prque: use int priority in some tests

No need to convert to int64 when we can just change the type used by the
queue.

* common/prque: remove comment about int64 range

---------

Co-authored-by: Zsolt Felfoldi <zsfelfoldi@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>

core/txpool/txpool.go

@@ -1395,7 +1395,7 @@ func (pool *TxPool) truncatePending() {
 
 	pendingBeforeCap := pending
 	// Assemble a spam order to penalize large transactors first
-	spammers := prque.New(nil)
+	spammers := prque.New[int64, common.Address](nil)
 	for addr, list := range pool.pending {
 		// Only evict transactions from high rollers
 		if !pool.locals.contains(addr) && uint64(list.Len()) > pool.config.AccountSlots {
@@ -1407,12 +1407,12 @@ func (pool *TxPool) truncatePending() {
 	for pending > pool.config.GlobalSlots && !spammers.Empty() {
 		// Retrieve the next offender if not local address
 		offender, _ := spammers.Pop()
-		offenders = append(offenders, offender.(common.Address))
+		offenders = append(offenders, offender)
 
 		// Equalize balances until all the same or below threshold
 		if len(offenders) > 1 {
 			// Calculate the equalization threshold for all current offenders
-			threshold := pool.pending[offender.(common.Address)].Len()
+			threshold := pool.pending[offender].Len()
 
 			// Iteratively reduce all offenders until below limit or threshold reached
 			for pending > pool.config.GlobalSlots && pool.pending[offenders[len(offenders)-2]].Len() > threshold {