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")
 			}

common/hstrings/strings_test.go

@@ -105,13 +105,13 @@ func BenchmarkUniqueStrings(b *testing.B) {
 	b.Run("Reuse slice sorted", func(b *testing.B) {
 		b.StopTimer()
 		inputs := make([][]string, b.N)
-		for i := 0; b.Loop(); i++ {
+		for i := 0; i < b.N; i++ {
 			inputc := make([]string, len(input))
 			copy(inputc, input)
 			inputs[i] = inputc
 		}
 		b.StartTimer()
-		for i := 0; b.Loop(); i++ {
+		for i := 0; i < b.N; i++ {
 			inputc := inputs[i]
 
 			result := UniqueStringsSorted(inputc)