Python: Do not alter codeql-workspaces.yml

And remove the qlpack referred to therein.
Instead we rename and duplicate the extesion file
that this qlpack pointed to.
These two extension files are kept in sync by `identical-files.json`.

python/ql/test/experimental/dataflow/model-summaries/NormalDataflowTest.ext.yml

@@ -0,0 +1,18 @@
+extensions:
+  - addsTo:
+      pack: codeql/python-all
+      extensible: summaryModel
+    data:
+      - ["foo", "Member[MS_identity]", "Argument[0]", "ReturnValue", "value"]
+      - ["foo", "Member[MS_apply_lambda]", "Argument[1]", "Argument[0].Parameter[0]", "value"]
+      - ["foo", "Member[MS_apply_lambda]", "Argument[0].ReturnValue", "ReturnValue", "value"]
+      - ["foo", "Member[MS_reversed]", "Argument[0].ListElement", "ReturnValue.ListElement", "value"]
+      - ["foo", "Member[MS_reversed]", "Argument[0]", "ReturnValue", "taint"]
+      - ["foo", "Member[MS_list_map]", "Argument[1].ListElement", "Argument[0].Parameter[0]", "value"]
+      - ["foo", "Member[MS_list_map]", "Argument[0].ReturnValue", "ReturnValue.ListElement", "value"]
+      - ["foo", "Member[MS_list_map]", "Argument[1]", "ReturnValue", "taint"]
+      - ["foo", "Member[MS_append_to_list]", "Argument[0].ListElement", "ReturnValue.ListElement", "value"]
+      - ["foo", "Member[MS_append_to_list]", "Argument[1]", "ReturnValue.ListElement", "value"]
+      - ["foo", "Member[MS_append_to_list]", "Argument[0]", "ReturnValue", "taint"]
+      - ["foo", "Member[MS_append_to_list]", "Argument[1]", "ReturnValue", "taint"]
+      - ["json", "Member[MS_loads]", "Argument[0]", "ReturnValue", "taint"]

python/ql/test/experimental/dataflow/model-summaries/qlpack.yml

@@ -1,11 +0,0 @@
-name: python-model-summaries-tests
-groups:
-    - python
-    - test
-dependencies:
-    codeql/python-tests: ${workspace}
-extractor: python
-tests: .
-warnOnImplicitThis: true
-dataExtensions:
-  - AllTests.ext.yml