Auto merge of #9186 - weihanglo:issue-9054, r=alexcrichton

Auto merge of #9186 - weihanglo:issue-9054, r=alexcrichton

Respect Cargo.toml `[package.exclude]` even not in a git repo.

May resolves #9054

This bug (or feature?) has been lingering for a while. #7680 fixed the `cargo package` part but `cargo vendor` is still affected by the heuristic rule of ignoring dotfiles. ~~I propose to drop the rule and include dotfiles by default even if the package is not under git-controlled~~. See below.

## Updated: Changes Summary

`cargo vendor` vendors dependencies without git-controlled but `cargo package` often runs under a VCS like git. [These lines](https://github.com/rust-lang/cargo/blob/1ca930b/src/cargo/sources/path.rs#L161-L168) are where they diverges: `fn list_files_walk_except_dot_files_and_dirs` builds [its own ignore instance], which cannot merge with other filter rules from `[package.exclude]`. This causes some patterns to not work as expected, such as re-including file after ignoring dotfiles `[.*, !negated_file]`.

To make re-include (negate) rule works, this patch adds the excluding dotfiles rule directly into the `package.exclude` ignore instance if **_no include option nor git repo exists_**. Other old behaviors should not change in this patch.

[its own ignore instance]: https://github.com/rust-lang/cargo/blob/1ca930b6/src/cargo/sources/path.rs#L364-L366