fix: pre-allocate certain slices with expected capacity (#12044)

Avoids append() based tiny allocations on known
allocated slices repeated access.

cmd/xl-storage-format-v2.go

@@ -1147,7 +1147,7 @@ func (z xlMetaV2) TotalSize() int64 {
 // showPendingDeletes is set to true if ListVersions needs to list objects marked deleted
 // but waiting to be replicated
 func (z xlMetaV2) ListVersions(volume, path string) ([]FileInfo, time.Time, error) {
-	var versions []FileInfo
+	versions := make([]FileInfo, 0, len(z.Versions))
 	var err error
 
 	for _, version := range z.Versions {