Rollup merge of #123107 - avandesa:vec_pop_if, r=joboet

Implement `Vec::pop_if`

This PR adds `Vec::pop_if` to the public API, behind the `vec_pop_if` feature.

```rust
impl<T> Vec<T> {
    pub fn pop_if<F>(&mut self, f: F) -> Option<T>
        where F: FnOnce(&mut T) -> bool;
}
```

Tracking issue: #122741

## Open questions

- [ ] Should the first unit test be split up?
- [ ] I don't see any guidance on ordering of methods in impl blocks, should I move the method elsewhere?

1 files changed, 1 insertions, 0 deletions

diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index f58998fbd79..04709af5c0a 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -43,6 +43,7 @@
 #![feature(strict_provenance)]
 #![feature(drain_keep_rest)]
 #![feature(local_waker)]
+#![feature(vec_pop_if)]
 #![allow(internal_features)]
 #![deny(fuzzy_provenance_casts)]
 #![deny(unsafe_op_in_unsafe_fn)]