Test files ( 'e' function )

[tonco-miyazawa]

This is a fix to make it "FAIL" when no error occurred.

The following four fixes:

oniguruma/test/test_utf8.c

Line 67 in ab444e0

if (r < ONIG_MISMATCH) {

oniguruma/test/test_syntax.c

Line 68 in ab444e0

if (r < ONIG_MISMATCH) {

oniguruma/test/test_options.c

Line 67 in ab444e0

if (r < ONIG_MISMATCH) {

oniguruma/test/test_back.c

Line 67 in ab444e0

if (r < ONIG_MISMATCH) {

Please rewrite it as follows.

//Before
if (r < ONIG_MISMATCH) {

//After
if (r < ONIG_MISMATCH || error_no < ONIG_MISMATCH) {

This will change the results of the following tests:

oniguruma/test/test_utf8.c

Lines 1651 to 1652 in ab444e0

	e("(?Ii)$", "", ONIGERR_INVALID_GROUP_OPTION);
	e("(?Ii)|", "", ONIGERR_INVALID_GROUP_OPTION);

and

  e("" , "" , -50000);
  e("a", "a", -50001);
  e("a", "b", -50002);

P.S. (*SKIP) worked fine. Thank you.