modernize: Use b.Loop (introduced in Go 1.24)

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

pkg/tailfile/tailfile_test.go

@@ -151,8 +151,8 @@ func BenchmarkTail(b *testing.B) {
 			b.Fatal(err)
 		}
 	}
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
+
+	for b.Loop() {
 		if _, err := TailFile(f, 1000); err != nil {
 			b.Fatal(err)
 		}