Reviewed by Alexey Proskuryakov.

        https://bugs.webkit.org/show_bug.cgi?id=32937
        LayoutTests/fast/encoding/invalid-UTF-8.html fails on Qt.

        The test was verifying two things: first, that U+FFFD is rendered by the browser, and second,
        that ill-formed UTF-8 sequences are turned into U+FFFD. Some aspects of the latter are not
        precisely defined by the Unicode specification, so different platforms may legitimately
        have different results.

        Split the test into two: one to test the rendering of invalid UTF-8 sequences, and the other
        to protect against regressions in each platform's decoding behaviour.

        * fast/encoding/invalid-UTF-8-2-expected.txt: Added.
        * fast/encoding/invalid-UTF-8-2.html: Added.
        * fast/encoding/invalid-UTF-8.html:
        * platform/mac/fast/encoding/invalid-UTF-8-expected.checksum:
        * platform/mac/fast/encoding/invalid-UTF-8-expected.png:
        * platform/mac/fast/encoding/invalid-UTF-8-expected.txt:
        * platform/qt/fast/encoding/invalid-UTF-8-2-expected.txt:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@55103 268f45cc-cd09-0410-ab3c-d52691b4dbfc