script/vm: mask systemd-tmpfiles-clean.timer

systemd-tmpfiles-clean.timer runs 15 minutes after boot and removes
empty directories under /tmp with mtimes older than 10 days. Some
integration tests place containerd's root in t.TempDir() and unpack
image layers with older directory timestamps under /tmp. If the timer
fires during extraction, systemd-tmpfiles removes newly created empty
directories before the final directory timestamp pass.

Assisted-by: Antigravity
Signed-off-by: Samuel Karp <samuelkarp@google.com>

script/vm/provision.sh

@@ -116,3 +116,9 @@ containerd-shim-runc-fp-v1 -v
 # and establish /etc/containerd/config.toml
 SELINUX="${SELINUX}" script/setup/config-selinux
 script/setup/config-containerd
+
+# systemd-tmpfiles-clean.timer runs 15 minutes after boot and removes empty
+# directories under /tmp with mtimes older than 10 days. Unpacking an image
+# layer under /tmp applies the layer's directory timestamps before finishing
+# extraction.
+systemctl mask --now systemd-tmpfiles-clean.timer