sort: fix a slice benchmark not using the stable variant, add another

Change-Id: I9783d8023d453a72c4605a308064bef98168bcb8
Reviewed-on: https://go-review.googlesource.com/30360Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/sort/sort_test.go

@@ -245,7 +245,7 @@ func BenchmarkStableInt1K_Slice(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		copy(data, unsorted)
 		b.StartTimer()
-		Slice(data, func(i, j int) bool { return data[i] < data[j] })
+		SliceStable(data, func(i, j int) bool { return data[i] < data[j] })
 		b.StopTimer()
 	}
 }
@@ -263,6 +263,19 @@ func BenchmarkSortInt64K(b *testing.B) {
 	}
 }
 
+func BenchmarkSortInt64K_Slice(b *testing.B) {
+	b.StopTimer()
+	for i := 0; i < b.N; i++ {
+		data := make([]int, 1<<16)
+		for i := 0; i < len(data); i++ {
+			data[i] = i ^ 0xcccc
+		}
+		b.StartTimer()
+		Slice(data, func(i, j int) bool { return data[i] < data[j] })
+		b.StopTimer()
+	}
+}
+
 func BenchmarkStableInt64K(b *testing.B) {
 	b.StopTimer()
 	for i := 0; i < b.N; i++ {