index/suffixarray: use built-in clear to simplify code

"sais2.go" is regenerated by the command "go generate ./...".

Change-Id: I4307e9fa1f20ea59e3a0d4841dbb22e9cffefa5a
GitHub-Last-Rev: d285183
GitHub-Pull-Request: #66376
Reviewed-on: https://go-review.googlesource.com/c/go/+/572198
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Robert Griesemer <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Reviewed-by: David Chase <[email protected]>
Commit-Queue: Ian Lance Taylor <[email protected]>

Author: apocelipes

src/index/suffixarray/sais.go

@@ -219,9 +219,7 @@ func freq_8_32(text []byte, freq, bucket []int32) []int32 {
 	}
 
 	freq = freq[:256] // eliminate bounds check for freq[c] below
-	for i := range freq {
-		freq[i] = 0
-	}
+	clear(freq)
 	for _, c := range text {
 		freq[c]++
 	}
@@ -710,9 +708,7 @@ func recurse_32(sa, oldTmp []int32, numLMS, maxID int) {
 	// sais_32 requires that the caller arrange to clear dst,
 	// because in general the caller may know dst is
 	// freshly-allocated and already cleared. But this one is not.
-	for i := range dst {
-		dst[i] = 0
-	}
+	clear(dst)
 	sais_32(text, maxID, dst, tmp)
 }