Add an ESP decryption test using the capture+keys from bug 12671.
Change-Id: I5f7ce477ec74d59c1043345728a1444842912b96
Ping-Bug: 12671
Reviewed-on: https://code.wireshark.org/review/16733
Reviewed-by: Gerald Combs <gerald@wireshark.org>
Tested-by: Gerald Combs <gerald@wireshark.org>