Tools/freeze/test/freeze.py fetches CONFIG_ARGS from the [clean] build directory, instead of fetching it from the source directory.

Discovered while working on #102131.

Linked PRs

• gh-102151: Correctly fetch CONFIG_ARGS in Tools/freeze/test/freeze.py #102152
• [3.11] gh-102151: Correctly fetch CONFIG_ARGS in Tools/freeze/test/freeze.py (GH-102152) #102176