Enhance printing of unfetchable object addresses in sequences and arrays

Enhance printing of unfetchable object addresses in sequences and arrays

* btrfs.c (btrfs_print_tree_search): Print the address of unfetchable
object inside the sequence using printaddr_comment.
* msghdr.c (decode_msg_control): Likewise.
* execve.c (printargv): Print the address of unfetchable object inside
the array using printaddr_comment.
* netlink.c (fetch_nlmsghdr): Add in_array argument.  When in_array
is true, print the address of unfetchable object using
printaddr_comment.
* nlattr.c (fetch_nlattr): Likewise.
* tests/execve.c (main): Update expected output.
* tests/execveat.c (main): Likewise.
* tests/msg_control.c (test_scm_rights1, test_scm_rights2,
test_scm_security): Likewise.
* tests/netlink_protocol.c (send_query): Likewise.
* tests/nlattr.c (test_nlattr): Likewise.