Modernize lib/auth and lib/utils (#55976)

lib/utils/sortcache/sortcache_test.go

@@ -18,7 +18,6 @@
 package sortcache
 
 import (
-	"context"
 	"slices"
 	"strconv"
 	"testing"
@@ -319,7 +318,7 @@ func BenchmarkSortCache(b *testing.B) {
 	cache.Put(r2)
 
 	// seed cache with lots of additional resources to help simulate large reads
-	for i := 0; i < resourcesPerKind-1; i++ {
+	for i := range resourcesPerKind - 1 {
 		cache.Put(resource{
 			kind: "node",
 			name: strconv.Itoa(i),
@@ -333,8 +332,7 @@ func BenchmarkSortCache(b *testing.B) {
 	// set up a background process to inject concurrent writes in a fairly
 	// tight loop (should roughly simulate the load generated by a background
 	// event stream injecting updates into a replica).
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
+	ctx := b.Context()
 	go func() {
 		for {
 			if ctx.Err() != nil {
@@ -346,7 +344,7 @@ func BenchmarkSortCache(b *testing.B) {
 	}()
 
 	// set up a bunch of background concurrent read operations to simulate load.
-	for i := 0; i < concurrency; i++ {
+	for range concurrency {
 		go func() {
 			var n int
 			buf := make([]resource, 0, resourcesPerKind)