Modify some unit tests for Models.Lzss as characterization tests
Modify some unit tests for Models.Lzss as characterization tests

Because Models.BitReader.ReadBits() doesn't throw EndOfStreamException.
See also 2e0a2ecacfab7921b1cbc5bac9930b99cc5ea6a4

y-iihoshi/ThScoreFileConverter,y-iihoshi/ThScoreFileConverter