Merge fix for double-free

Original commit messages:
commit 8a1b05c3a8b6a46dee59e4fd48a0eea2c09a91a4
Author: sumit.ray@baesystems.com <sumit.ray@baesystems.com>
Date:   Fri Feb 4 16:19:35 2022 -0500

    Removed check for null trailer - files using xref content streams may not have a the keyword trailer

commit 98378f2603fd1b4b93ca06d06b079ed81f284e0c
Author: sumit.ray@baesystems.com <sumit.ray@baesystems.com>
Date:   Fri Feb 4 10:25:15 2022 -0500

    Added commentary for a semantically more meaningful error message when the xref offset specified is outside bounds

commit 7cc9be2beea026219f6c2b851eaac0d5bf8d8cba
Author: sumit.ray@baesystems.com <sumit.ray@baesystems.com>
Date:   Thu Feb 3 18:14:55 2022 -0500

    Fix for double-free - added guard for invalid trailer section