[libzstd] Fix bug in Huffman decompresser

[libzstd] Fix bug in Huffman decompresser

The zstd format specification doesn't enforce that Huffman compressed
literals (including the table) have to be smaller than the uncompressed
literals. The compressor will never Huffman compress literals if the
compressed size is larger than the uncompressed size. The decompresser
doesn't accept Huffman compressed literals with 4 streams whose compressed
size is at least as large as the uncompressed size.

* Make the decompresser accept Huffman compressed literals whose size
  increases.
* Add a test case that exposes the bug. The compressed file has to be
  statically generated, since the compressor won't normally produce files
  that expose the bug.