use standard vm

tests/cloud_playbooks/create-gce.yml

@@ -3,7 +3,7 @@
   become: false
   gather_facts: no
   vars:
-    cloud_machine_type: g1-small
+    cloud_machine_type: n1-standard-1
     mode: default
 
   tasks:

tests/cloud_playbooks/delete-gce.yml

@@ -23,6 +23,7 @@
       gce:
         instance_names: "{{instance_names}}"
         machine_type: "{{ cloud_machine_type }}"
+        preemptible: yes
         image: "{{ cloud_image }}"
         service_account_email: "{{ gce_service_account_email }}"
         pem_file: "{{ gce_pem_file | default(omit)}}"