This fixes a regression from dd615c8fdd that moved the
newIPTablesRunner constructor from a any-Linux-GOARCH file to one that
was only amd64 and arm64, thus breaking iptables on other platforms
(notably 32-bit "arm", as seen on older Pis running Buster with
iptables)
Tested by hand on a Raspberry Pi 2 w/ Buster + iptables for now, for
lack of automated 32-bit arm tests at the moment. But filed #17629.
Fixes#17623
Updates #17629
Change-Id: Iac1a3d78f35d8428821b46f0fed3f3717891c1bd
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
(cherry picked from commit 8576a802ca)
c81ef9055b