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>

eth/fetcher/block_fetcher.go

@@ -175,9 +175,9 @@ type BlockFetcher struct {
 	completing map[common.Hash]*blockAnnounce   // Blocks with headers, currently body-completing
 
 	// Block cache
-	queue  *prque.Prque                         // Queue containing the import operations (block number sorted)
-	queues map[string]int                       // Per peer block counts to prevent memory exhaustion
-	queued map[common.Hash]*blockOrHeaderInject // Set of already queued blocks (to dedup imports)
+	queue  *prque.Prque[int64, *blockOrHeaderInject] // Queue containing the import operations (block number sorted)
+	queues map[string]int                            // Per peer block counts to prevent memory exhaustion
+	queued map[common.Hash]*blockOrHeaderInject      // Set of already queued blocks (to dedup imports)
 
 	// Callbacks
 	getHeader      HeaderRetrievalFn  // Retrieves a header from the local chain
@@ -212,7 +212,7 @@ func NewBlockFetcher(light bool, getHeader HeaderRetrievalFn, getBlock blockRetr
 		fetching:       make(map[common.Hash]*blockAnnounce),
 		fetched:        make(map[common.Hash][]*blockAnnounce),
 		completing:     make(map[common.Hash]*blockAnnounce),
-		queue:          prque.New(nil),
+		queue:          prque.New[int64, *blockOrHeaderInject](nil),
 		queues:         make(map[string]int),
 		queued:         make(map[common.Hash]*blockOrHeaderInject),
 		getHeader:      getHeader,
@@ -351,7 +351,7 @@ func (f *BlockFetcher) loop() {
 		// Import any queued blocks that could potentially fit
 		height := f.chainHeight()
 		for !f.queue.Empty() {
-			op := f.queue.PopItem().(*blockOrHeaderInject)
+			op := f.queue.PopItem()
 			hash := op.hash()
 			if f.queueChangeHook != nil {
 				f.queueChangeHook(hash, false)