[NFC] Delete unused clang-formatted-file.txt/ClangFormattedStatus.rst files (llvm#109220)

Looks like these files are generated by the
`generate_formatted_state.py` script as a "status report" of state of
clang-format compliance of files in the LLVM git repo. As such, they do
not belong to the repo itself, so deleting them.

Please see:
https://discourse.llvm.org/t/clang-docs-tools-clang-formatted-files-txt/82803

Author: jurahul