tests: save/restore Autotest special files when checking XML support.

Currently the test 248, "parse-gram.y: LALR = IELR", fails
BISON_TEST_XML is set.

* tests/local.at (AT_BISON_CHECK_XML): Belt: Save/restore files.
* tests/regression.at (parse-gram.y: LALR = IELR): Suspenders: Don't
rely on expout.
Each one of these changes suffices.

tests/local.at

@@ -373,8 +373,9 @@ m4_if(m4_bregexp([$4], [: warning: ]), [-1], [],
 # defined.  It doesn't make sense to invoke this macro if Bison is expected to
 # have a non-zero exit status.
 m4_define([AT_BISON_CHECK_XML],
-[[if test x"$BISON_TEST_XML" = x1 && test x"$XSLTPROC" != x""; then
-  mkdir xml-tests]
+[[if test x"$BISON_TEST_XML" = x1 && test x"$XSLTPROC" != x""; then]
+  AT_SAVE_SPECIAL_FILES
+  [mkdir xml-tests]
   m4_pushdef([AT_BISON_ARGS],
              [m4_bpatsubsts([[$1]],
                             [--report(-file)?=[^][ ]*], [],
@@ -396,8 +397,9 @@ m4_define([AT_BISON_CHECK_XML],
   AT_CHECK([[$XSLTPROC \
              `]]AT_QUELL_VALGRIND[[ bison --print-datadir`/xslt/xml2dot.xsl \
              xml-tests/test.xml]], [[0]], [expout])
-  [rm -rf xml-tests expout
-fi]])
+  [rm -rf xml-tests expout]
+  AT_RESTORE_SPECIAL_FILES
+[fi]])
 
 # AT_QUELL_VALGRIND
 # -----------------

tests/regression.at

@@ -1266,10 +1266,12 @@ AT_SETUP([[parse-gram.y: LALR = IELR]])
 # have the same name.
 [cp $abs_top_srcdir/src/parse-gram.y input.y]
 AT_BISON_CHECK([[-o input.c -Dlr.type=lalr input.y]])
-[mv input.c expout]
+[mv input.c lalr.c]
+AT_CAPTURE_FILE([lalr.c])
 AT_BISON_CHECK([[-o input.c -Dlr.type=ielr input.y]])
 [mv input.c ielr.c]
-AT_CHECK([[cat ielr.c]], [[0]], [[expout]])
+AT_CAPTURE_FILE([ielr.c])
+AT_CHECK([[diff lalr.c ielr.c]], [[0]])
 
 AT_CLEANUP