python: fix test expectations

also rename `collections.py` so it does not
clash with the standard library name.
This clash is an issue when testing locally.

Author: yoff

python/ql/test/experimental/dataflow/variable-capture/CaptureTest.expected

@@ -0,0 +1 @@
+| test_collections.py:55:6:55:16 | ControlFlowNode for Subscript | Fixed missing result:captured= |

python/ql/test/experimental/dataflow/variable-capture/dataflow-consistency.expected

@@ -1,10 +1,11 @@
 uniqueEnclosingCallable
 uniqueCallEnclosingCallable
-| collections.py:39:17:39:38 | Lambda() | Call should have one enclosing callable but has 0. |
-| collections.py:39:17:39:38 | Lambda() | Call should have one enclosing callable but has 0. |
-| collections.py:45:19:45:24 | mod() | Call should have one enclosing callable but has 0. |
-| collections.py:45:19:45:24 | mod() | Call should have one enclosing callable but has 0. |
-| collections.py:52:13:52:24 | mod_local() | Call should have one enclosing callable but has 0. |
+| test_collections.py:39:17:39:38 | Lambda() | Call should have one enclosing callable but has 0. |
+| test_collections.py:39:17:39:38 | Lambda() | Call should have one enclosing callable but has 0. |
+| test_collections.py:45:19:45:24 | mod() | Call should have one enclosing callable but has 0. |
+| test_collections.py:45:19:45:24 | mod() | Call should have one enclosing callable but has 0. |
+| test_collections.py:52:13:52:24 | mod_local() | Call should have one enclosing callable but has 0. |
+| test_collections.py:52:13:52:24 | mod_local() | Call should have one enclosing callable but has 0. |
 uniqueType
 uniqueNodeLocation
 missingLocation