So that the impact of the commit that fixes the test can be seen
clearly.

When there is a lifetime error, the code does its best to find variables
that correspond to the lifetimes involved. This commit stops mentioning
arguments that are unused in closures, since they are not relevant.

See the diff of the blessed test to get a good clue of what that means.

given

…lubby789,jieyouxu

Make sure we run the full suite, even when more specific filters are given

Some test suite's filter code took this into account, while others didn't.
Imagine this:

```
x test tests/ui/sometest.rs tests/ui
```

This would run only `tests/ui/sometest.rs` since we filtered out `tests/ui` since it matches the name of the test suite.
The reason `x test tests/ui` on its own works, is that if compiletest gets no filter paths, only a suite, it runs the entire suite.
What I've implemented here is that when you pass the suite path, we effectively ignore specific filters and just run the entire suite since that'll include the more specific paths too. This was the case for a few other suites as well, like rustdocjs, but others actually handle this correctly (like clippy, which my code does edit but for which the behavior doesn't change).

Hope this makes sense!

…mann

borrowck: Don't mention unused vars in closure outlive errors

When there is a closure arg lifetime error, the code does its best to find variables that correspond to the lifetimes involved. This commit stops mentioning arguments that are unused in closures, since they are not relevant. This removes the "red herring" of rust-lang#113121.

The `user_arg_index` nomenclature can be applied more broadly, but then the diff becomes annoyingly big, so I chose not to do that.

Review each commit individually for a nicer experience.