all: Fix some benchmarks broken by modernize

It's not possible to use `b.Loop()` when `b.N` is used to prepare test data.

See 264022a75a
See #14107

common/hreflect/helpers_test.go

@@ -161,7 +161,7 @@ func BenchmarkIsContextType(b *testing.B) {
 		}
 
 		b.ResetTimer()
-		for i := 0; b.Loop(); i++ {
+		for i := 0; i < b.N; i++ {
 			if !IsContextType(ctxs[i]) {
 				b.Fatal("not context")
 			}