Auto merge of #121635 - 823984418:remove_archive_builder_lifetime_a, r=nnethercote

Remove useless lifetime of ArchiveBuilder

`trait ArchiveBuilder<'a>` has a seemingly useless lifetime a, so I remove it. If this is intentional, please reject this PR.

```rust
pub trait ArchiveBuilder<'a> {
    fn add_file(&mut self, path: &Path);

    fn add_archive(
        &mut self,
        archive: &Path,
        skip: Box<dyn FnMut(&str) -> bool + 'static>,
    ) -> io::Result<()>;

    fn build(self: Box<Self>, output: &Path) -> bool;
}
```

Author: bors

src/archive.rs

@@ -8,7 +8,7 @@ use rustc_session::Session;
 pub(crate) struct ArArchiveBuilderBuilder;
 
 impl ArchiveBuilderBuilder for ArArchiveBuilderBuilder {
-    fn new_archive_builder<'a>(&self, sess: &'a Session) -> Box<dyn ArchiveBuilder<'a> + 'a> {
+    fn new_archive_builder<'a>(&self, sess: &'a Session) -> Box<dyn ArchiveBuilder + 'a> {
         Box::new(ArArchiveBuilder::new(sess, get_native_object_symbols))
     }