Misc: Add script to accept .expected changes from CI

This script can be used to go over `codeql test run` expected/actual log
output from actions CI checks for a PR, and apply patches locally to
make the tests pass.

Designed for use by GitHub employees, since it needs access to internal
CI runs. Just run this tool while the branch for the PR is checked out!

You need the `gh` cli tool installed and authenticated.

Example can be seen in https://github.com/github/codeql/pull/12950

.vscode/tasks.json

@@ -22,6 +22,22 @@
                 "command": "${config:python.pythonPath}",
             },
             "problemMatcher": []
+        },
+        {
+            "label": "Accept .expected changes from CI",
+            "type": "process",
+            // Non-Windows OS will usually have Python 3 already installed at /usr/bin/python3.
+            "command": "python3",
+            "args": [
+                "misc/scripts/accept-expected-changes-from-ci.py"
+            ],
+            "group": "build",
+            "windows": {
+                // On Windows, use whatever Python interpreter is configured for this workspace. The default is
+                // just `python`, so if Python is already on the path, this will find it.
+                "command": "${config:python.pythonPath}",
+            },
+            "problemMatcher": []
         }
     ]
-}
+}