fix stderr/stdout redirection in tests

tests/test.sh

@@ -6,8 +6,8 @@ FILTER="${1:-}"
 : "${DEBUG:=false}"
 if "$DEBUG"
 then
-	REDIR1="&1"
-	REDIR2="&2"
+	REDIR1=/proc/self/fd/1
+	REDIR2=/proc/self/fd/2
 else
 	REDIR1=/dev/null
 	REDIR2=/dev/null