[System.IO.Compression] Fixed DeflateStream inflate() decompression loop.

[System.IO.Compression] Fixed DeflateStream inflate() decompression loop.

This reworks the fix from https://github.com/mono/mono/commit/7c4d41a518aaf0370b882f9430752ebcd5544c10.

That fix introduced a regression when handling some inputs, which lead us to ignore
some left-over data from zlib's inflate output buffer.

Now we only break from the loop if inflate() returns Z_BUF_ERROR.

This makes sure all data is fully processed before returning to managed code.

Fixes one of the bugs in https://bugzilla.xamarin.com/show_bug.cgi?id=44994#c2.