I had the same issue, asked in chat, and was directed to this question. I have solved it on my machine so I'll just relate what I was told.
You need to revert the
l3packages to the previous version. The command is
$ tlmgr restore l3packages
(probably prefix that command with
sudo to run as root) If no revision number is specified, all available previous revisions are listed.
The response I got was
Do you really want to restore l3packages to revision 44864 (y/N):
y, I got
Restoring l3packages, 44864 from /usr/local/texlive/2016/tlpkg/backups/l3packages.r44864.tar.xz
And after that everything worked again.
According to comments by Christian and Nasser, not everybody's
tlmgr restore is interactive like the one above. It may be the case that you just get the list of previously installed revisions. If so, choose the largest-numbered (i.e., most recent, not counting the current one), revision NUM, and type
$ tlmgr restore l3packages <NUM>