Cover UTF-8 limit correction; some tests fail

Failing tests are:
[-] UTF-8 case  3: Expected movement by -1 chars, actually moved by  0 chars: "\xdf"
[-] UTF-8 case  4: Expected movement by  0 chars, actually moved by -1 chars: "\xdf\xbf"
[-] UTF-8 case  5: Expected movement by -1 chars, actually moved by  0 chars: "\xef"
[-] UTF-8 case  6: Expected movement by -2 chars, actually moved by -1 chars: "\xef\xbf"
[-] UTF-8 case  7: Expected movement by  0 chars, actually moved by -2 chars: "\xef\xbf\xbf"
[-] UTF-8 case  8: Expected movement by -1 chars, actually moved by  0 chars: "\xf7"
[-] UTF-8 case  9: Expected movement by -2 chars, actually moved by -1 chars: "\xf7\xbf"
[-] UTF-8 case 10: Expected movement by -3 chars, actually moved by -2 chars: "\xf7\xbf\xbf"
[-] UTF-8 case 11: Expected movement by  0 chars, actually moved by -3 chars: "\xf7\xbf\xbf\xbf"
3 files changed
tree: 00fb0e90ded7f6f2423c26c27565b42d3b7cd0e8
  1. .gitignore
  2. expat/
  3. htdocs/
  4. testdata/