correct Unicode to/from Single-Byte map of test case "test_singlebyte_conv()"

References:
http://en.wikipedia.org/wiki/ISO/IEC_8859-7
http://en.wikipedia.org/wiki/ISO/IEC_8859-8
http://en.wikipedia.org/wiki/ISO/IEC_8859-11
http://en.wikipedia.org/wiki/Windows-1255