test: install split-out sshd-session binary if present

Archlinux split out one ssh binary, install it in the legacy test
setup if present for the tests that need ssh

test/TEST-46-HOMED/test.sh

@@ -24,6 +24,7 @@ test_append_files() {
     inst_binary ssh
     inst_binary sshd
     inst_binary ssh-keygen
+    image_install -o /usr/lib/ssh/sshd-session
 }
 
 do_test "$@"

test/TEST-74-AUX-UTILS/test.sh

@@ -31,6 +31,7 @@ test_append_files() {
     inst_binary ssh
     inst_binary sshd
     inst_binary ssh-keygen
+    image_install -o /usr/lib/ssh/sshd-session
     inst_binary usermod
     instmods vmw_vsock_virtio_transport
     instmods vsock_loopback