sort: rename helpers: s/Sort// in sort.Sort[Float64s|Ints|Strings]

Includes 'sorthelpers' gofix and updates to tree.

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/4631098
diff --git a/src/pkg/index/suffixarray/suffixarray.go b/src/pkg/index/suffixarray/suffixarray.go
index 079b7d8..9d4e932 100644
--- a/src/pkg/index/suffixarray/suffixarray.go
+++ b/src/pkg/index/suffixarray/suffixarray.go
@@ -115,7 +115,7 @@
 			if len(indices) == 0 {
 				return
 			}
-			sort.SortInts(indices)
+			sort.Ints(indices)
 			pairs := make([]int, 2*len(indices))
 			result = make([][]int, len(indices))
 			count := 0
@@ -159,7 +159,7 @@
 		if len(indices) == 0 {
 			return
 		}
-		sort.SortInts(indices)
+		sort.Ints(indices)
 		result = result[0:0]
 		prev := 0
 		for _, i := range indices {