deflate_compress: strengthen levels 10-12 slightly
deflate_compress: strengthen levels 10-12 slightly

With deflate_compress_near_optimal(), some data benefits more than
originally thought from larger values of max_search_depth and
nice_match_length.  Some data even needs these parameters to be fairly
high for deflate_compress_near_optimal() to compress more than
deflate_compress_lazy2().  Bump these parameters up a bit.

ebiggers/libdeflate,ebiggers/libdeflate,ebiggers/libdeflate