Re-enable support for nested KVM.

This is apparently still needed by the "Android Testing" pipeline.

This reverts commit a7c9a468efaf2336001ea54855a4d1b9b35918cd.
diff --git a/buildkite/create_images.py b/buildkite/create_images.py
index c626b32..0cf60c7 100755
--- a/buildkite/create_images.py
+++ b/buildkite/create_images.py
@@ -36,6 +36,9 @@
         "source_image_family": "ubuntu-1804-lts",
         "setup_script": "setup-docker.sh",
         "guest_os_features": ["VIRTIO_SCSI_MULTIQUEUE"],
+        "licenses": [
+            "https://www.googleapis.com/compute/v1/projects/vm-options/global/licenses/enable-vmx"
+        ],
     },
     "bk-testing-windows": {
         "project": "bazel-public",
diff --git a/buildkite/promote_images.py b/buildkite/promote_images.py
index e7b2ada..a016a20 100755
--- a/buildkite/promote_images.py
+++ b/buildkite/promote_images.py
@@ -28,6 +28,9 @@
         "source_image_project": "bazel-public",
         "source_image_family": "bk-testing-docker",
         "guest_os_features": ["VIRTIO_SCSI_MULTIQUEUE"],
+        "licenses": [
+            "https://www.googleapis.com/compute/v1/projects/vm-options/global/licenses/enable-vmx"
+        ],
     },
     "bk-windows": {
         "project": "bazel-public",