PyTorch fixes linter reliability in partial git clones with PR #191364

The PyTorch team tackled a recurring issue where linters in CI would fail due to partial git clones. Previous attempts, like PR #191228, enforced strict local-only git commands, but this caused errors when accessing historical file versions. The new approach, implemented in PR #191364 by janeyx99 and Codex, separates git commands into two categories: those that must remain offline and those that may contact the network.

Offline commands include merge-base with origin/main, working-tree diff, and initial attempts at historical object commands. These rely on the local checkout's full commit history. Network-dependent commands (latter attempts at historical file content) use `git diff`, `git ls-tree`, and `git cat-file` after a local failure. The fix also removes `git ls-remote`, explicit `git fetch origin <oid>`, and automatic ref updates, preventing conflicts from concurrent lint runs. This design ensures stable linter execution even with treeless checkouts and fetch-depth:0.