end the zlib stream when readDataBlock and sync throw

[ArjunD3456]

What is the purpose of the change

DataFileReaderBase::readDataBlock sets up a z_stream with inflateInit2 for every deflate-coded block it reads and only reaches the matching inflateEnd once the inflate loop has run to completion. When a block does not inflate, the throw inside that loop leaves the scope with the stream still live, so the ~7 KiB of state zlib allocated for it is lost. The payload comes straight from the file, so any corrupt or crafted container leaks it, and a process that keeps reading untrusted files and handles avro::Exception grows without bound. DataFileWriterBase::sync has the same shape around deflateInit2, and the resize call in either loop can leave the scope the same way. Giving the stream a small scope guard puts the inflateEnd/deflateEnd call on every exit path, which is how ZstdCompressWrapper and ZstdDecompressWrapper already release their contexts.

Verifying this change

This change added tests and can be verified as follows:

• added testCorruptDeflateBlock to DataFileTests, which writes a deflate file, rewrites the first payload byte so the block header carries the reserved RFC 1951 BTYPE 3, and checks the read is rejected rather than decoded; ./build.sh test and ./build.sh lint both stay green
• measured the leak: reading that file 2000 times and catching the exception each time grew the heap by 14336048 bytes (7168 per failed read) before this change and by 48 bytes after

Documentation

• Does this pull request introduce a new feature? no