m/test/launch/cluster: make node images use qcow2-based snapshots instead of copying

This is a mild speedup, saving a few seconds from every E2E test (time
which would've otherwise been spent copying image blocks) and
alleviating IOPS pressure as the test runs on tests which don't use
integrity checking.

Change-Id: I8feece1c028b62e54dc0b45732443d7c93515d7f
Reviewed-on: https://review.monogon.dev/c/monogon/+/3093
Reviewed-by: Jan Schär <jan@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/test/launch/cluster/BUILD.bazel b/metropolis/test/launch/cluster/BUILD.bazel
index 4b935f0..2685e2c 100644
--- a/metropolis/test/launch/cluster/BUILD.bazel
+++ b/metropolis/test/launch/cluster/BUILD.bazel
@@ -19,6 +19,7 @@
     importpath = "source.monogon.dev/metropolis/test/launch/cluster",
     visibility = ["//visibility:public"],
     deps = [
+        "//go/qcow2",
         "//metropolis/cli/metroctl/core",
         "//metropolis/node",
         "//metropolis/node/core/curator/proto/api",