Fix issue 18889: test_sax: multiple failures on Windows desktop.

"The fix" is to tell Mercurial that the test files are binary.

Windows developers:  to get the correct line endings in your checkout,
delete Lib\test\xmltestdata, and then "hg revert" that directory.

Why the Windows buildbots didn't fail test_sax remains a mystery :-(

.hgeol

@@ -31,6 +31,7 @@ Lib/test/cjkencodings/* = BIN
 Lib/test/decimaltestdata/*.decTest = BIN
 Lib/test/sndhdrdata/sndhdr.* = BIN
 Lib/test/test_email/data/msg_26.txt = BIN
+Lib/test/xmltestdata/* = BIN
 
 Lib/venv/scripts/nt/* = BIN