removed duplicate install and added debug dump of collection loading to see what tests are doing

.ci/localhost_ansible_install.py

@@ -14,7 +14,7 @@ batches = [
         # 'pip install -q ansible=={}'.format(ci_lib.ANSIBLE_VERSION)
         # ansible v2.10 isn't out yet so we're installing from github for now
         # Don't set -U as that will upgrade Paramiko to a non-2.6 compatible version.
-        'pip install -q virtualenv {}'.format(ci_lib.ANSIBLE_VERSION)
+        'pip install -q {}'.format(ci_lib.ANSIBLE_VERSION)
     ]
 ]
 

ansible_mitogen/planner.py

@@ -577,6 +577,8 @@ def _load_collections(invocation):
 
             for collection in collections:
                 invocation._extra_sys_paths.add(collection.b_path.decode('utf-8'))
+    # find out what tests are doing differently
+    raise ValueError(invocation._extra_sys_paths)
 
 
 def invoke(invocation):