Testcase for Mozilla bug 760050: §9

https://bugzilla.mozilla.org/show_bug.cgi?id=760050

With Character Encoding Auto-Detect set to Universal, the file should be
recognized as UTF-8 with a U+00A7 SECTION SIGN being displayed before 9,
instead of being regarded as TIS-620.

The bug occurs when the file is served with the "file:" URL scheme or by
HTTP as text/plain without a declared charset.