tests: use ls instead of find, all files are in the same directory

In this case find has no advantage compared to ls. Descending into directories
is unnecessary, because there are none.

tests/test-gendoc.t

@@ -1,61 +1,61 b''
 Test document extraction
 
   $ "$TESTDIR/hghave" docutils || exit 80
   $ HGENCODING=UTF-8
   $ export HGENCODING
-  $ { echo C; find "$TESTDIR/../i18n" -name "*.po" | sort; } | while read PO; do
+  $ { echo C; ls "$TESTDIR/../i18n"/*.po | sort; } | while read PO; do
   >     LOCALE=`basename "$PO" .po`
   >     echo
   >     echo "% extracting documentation from $LOCALE"
   >     echo ".. -*- coding: utf-8 -*-" > gendoc-$LOCALE.txt
   >     echo "" >> gendoc-$LOCALE.txt
   >     LANGUAGE=$LOCALE python "$TESTDIR/../doc/gendoc.py" >> gendoc-$LOCALE.txt 2> /dev/null || exit
   > 
   >     if [ $LOCALE != C ]; then
   >         cmp -s gendoc-C.txt gendoc-$LOCALE.txt && echo '** NOTHING TRANSLATED **'
   >     fi
   > 
   >     # We call runrst without adding "--halt warning" to make it report
   >     # all errors instead of stopping on the first one.
   >     echo "checking for parse errors"
   >     python "$TESTDIR/../doc/runrst" html gendoc-$LOCALE.txt /dev/null
   > done
   
   % extracting documentation from C
   checking for parse errors
   
   % extracting documentation from da
   checking for parse errors
   
   % extracting documentation from de
   checking for parse errors
   
   % extracting documentation from el
   checking for parse errors
   
   % extracting documentation from fr
   checking for parse errors
   
   % extracting documentation from it
   checking for parse errors
   
   % extracting documentation from ja
   checking for parse errors
   
   % extracting documentation from pt_BR
   checking for parse errors
   
   % extracting documentation from ro
   checking for parse errors
   
   % extracting documentation from ru
   checking for parse errors
   
   % extracting documentation from sv
   checking for parse errors
   
   % extracting documentation from zh_CN
   checking for parse errors
   
   % extracting documentation from zh_TW
   checking for parse errors