We now have the actual module that we need to build, so switch to
building it directly instead of its (expected) dependencies.
Also fix a copy/paste error in a jsdeps comment.
Signed-off-by: Mihai Parparita <mihai@tailscale.com>
For now just checks that we can build cmd/tailscale/cli, will be
broadened once we can actually build more things.
Updates #3157
Signed-off-by: Mihai Parparita <mihai@tailscale.com>