[release/6.0-rc1] Enable SocketHttpHandler to decompress zlib or deflate (#57940)

[release/6.0-rc1] Enable SocketHttpHandler to decompress zlib or deflate (#57940)

* Enable SocketHttpHandler to decompress zlib or deflate

Some servers incorrectly implement the deflate content-coding with the raw deflate algorithm rather than with deflate wrapped with a zlib header/footer.  Auto-detect whether to use ZLibStream or DeflateStream in order to accomodate both kinds of responses.

* Fix test build for WinHttpHandler on .NET Framework

* Apply suggestions from code review

* Add decompression test for empty response body

* Add decompression tests for multiple source content lengths

Co-authored-by: Stephen Toub <stoub@microsoft.com>