time: Fix ordering of slots in AfterQueueing test

We shouldn't sort the slots array, as it is used each time the
test is run.  Tests after the first should continue to use the
unsorted ordering.

Note that this doesn't fix the flaky test.  Just a bug I saw
while investigating.

Change-Id: Ic03cca637829d569d50d3a2278d19410d4dedba9
Reviewed-on: https://go-review.googlesource.com/9637Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/time/sleep_test.go

@@ -8,7 +8,6 @@ import (
 	"errors"
 	"fmt"
 	"runtime"
-	"sort"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -261,14 +260,21 @@ func testAfterQueuing(t *testing.T, delta Duration) error {
 	for _, slot := range slots {
 		go await(slot, result, After(Duration(slot)*delta))
 	}
-	sort.Ints(slots)
-	for _, slot := range slots {
+	var order []int
+	var times []Time
+	for range slots {
 		r := <-result
-		if r.slot != slot {
-			return fmt.Errorf("after slot %d, expected %d", r.slot, slot)
+		order = append(order, r.slot)
+		times = append(times, r.t)
+	}
+	for i := range order {
+		if i > 0 && order[i] < order[i-1] {
+			return fmt.Errorf("After calls returned out of order: %v", order)
 		}
-		dt := r.t.Sub(t0)
-		target := Duration(slot) * delta
+	}
+	for i, t := range times {
+		dt := t.Sub(t0)
+		target := Duration(order[i]) * delta
 		if dt < target-delta/2 || dt > target+delta*10 {
 			return fmt.Errorf("After(%s) arrived at %s, expected [%s,%s]", target, dt, target-delta/2, target+delta*10)
 		}