[clang-format] Exit clang-format-diff only after all diffs are printed (#86776)

See
https://github.com/llvm/llvm-project/pull/70883#issuecomment-2020811077.

NOKEYCHECK=True
GitOrigin-RevId: d9e3e11ae57612ec61f6fcab4afc27d8d0ff5841
1 file changed