builtin: fix substr()

vlib/builtin/string.v

@@ -604,18 +604,18 @@ fn (s string) substr2(start int, _end int, end_max bool) string {
 // Example: assert 'ABCD'.substr(1,3) == 'BC'
 pub fn (s string) substr(start int, end int) string {
 	$if !no_bounds_checking ? {
+		if start > end || start > s.len || end > s.len || start < 0 || end < 0 {
 			/*
 			$if debug {
-			if start > end || start > s.len || end > s.len || start < 0 || end < 0 {
 					println('substr($start, $end) out of bounds (len=$s.len)')
 					println('s="$s"')
 					print_backtrace()
 					return ''
 			}
-		}
 			*/
 			panic('substr($start, $end) out of bounds (len=$s.len)')
 		}
+	}
 	len := end - start
 	if len == s.len {
 		return s.clone()