Stop crypt($tied,...) from calling FETCH twice

It was doing so if FETCH returned a UTF8 string the first time.  It
then turned on the UTF8 flag on the result of the second FETCH, even
if it wasn’t UTF8:

$ ./miniperl -e 'sub TIESCALAR{bless[substr(chr 256,0,0), chr 255]} sub FETCH{shift @{$_[0]}}tie $t, ""; crypt $t, ""'
Wide character in crypt at -e line 1.

(There are no wide characters fed to crypt() there.)

1 files changed, 8 insertions, 1 deletions

diff --git a/t/op/tie_fetch_count.t b/t/op/tie_fetch_count.t
index 6955d19a76..28a4355478 100644
--- a/t/op/tie_fetch_count.t
+++ b/t/op/tie_fetch_count.t
@@ -7,7 +7,7 @@ BEGIN {
     chdir 't' if -d 't';
     require './test.pl';
     set_up_inc('../lib');
-    plan (tests => 340);
+    plan (tests => 344);
 }
 
 use strict;
@@ -244,6 +244,13 @@ for ([chdir=>''],[chmod=>'0,'],[chown=>'0,0,'],[utime=>'0,0,'],
     check_count "$op $args\\\$tied_glob$postargs";
 }
 
+$dummy  =   crypt $var,0; check_count 'crypt $tied, ...';
+$dummy  =   crypt 0,$var; check_count 'crypt ..., $tied';
+$var = substr(chr 256,0,0);
+$dummy  =   crypt $var,0; check_count 'crypt $tied_utf8, ...';
+$var = substr(chr 256,0,0);
+$dummy  =   crypt 0,$var; check_count 'crypt ..., $tied_utf8';
+
 {
     no warnings;
     $var = *foo;