Parse deflates in gzip files.

The diff for NOTICE.xml.gz is reduced from 200+K to 17K.

Also we are now honoring puffin::LocateDeflatesInGzip() failures,
since if won't complain about padding data anymore, and
puffin::LocateDeflateSubBlocksInZipArchive() is updated to
puffin::LocateDeflatesInZipArchive().

Test: generate a delta payload extracting deflates in gzip

Change-Id: I44b816cff8ac99ce78f758eef5875fa99e36e369