ash: fix a bug where redirection fds were not closed afterwards.
optimize close+fcntl(DUPFD) into dup2. add testsuites.
function old new delta
copyfd 47 68 +21
argstr 1311 1298 -13
popredir 148 131 -17
redirect 1139 1107 -32
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/3 up/down: 21/-62) Total: -41 bytes
diff --git a/shell/ash_test/ash-redir/redir2.tests b/shell/ash_test/ash-redir/redir2.tests
new file mode 100755
index 0000000..61ccea3
--- /dev/null
+++ b/shell/ash_test/ash-redir/redir2.tests
@@ -0,0 +1,5 @@
+# ash once couldn't redirect above fd#9
+exec 1>/dev/null
+(echo LOST1 >&22) 22>&1
+(echo LOST2 >&22) 22>&1
+(echo OK >&22) 22>&2