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

src/pkg/index/suffixarray/suffixarray_test.go

@@ -141,7 +141,7 @@ func testLookup(t *testing.T, tc *testCase, x *Index, s string, n int) {
 	// we cannot simply check that the res and exp lists are equal
 
 	// check that each result is in fact a correct match and there are no duplicates
-	sort.SortInts(res)
+	sort.Ints(res)
 	for i, r := range res {
 		if r < 0 || len(tc.source) <= r {
 			t.Errorf("test %q, lookup %q, result %d (n = %d): index %d out of range [0, %d[", tc.name, s, i, n, r, len(tc.source))