tests/ui/async-await/drop-option-future.rs: New regression test

[Enselic]

The test began compiling with nightly-2022-11-25. I bisected it further, and the commit that made it compile was 9f36f98 (#104321). The test fails to compile with nightly-2022-11-24:

$ rustc +nightly-2022-11-24 --edition 2018 tests/ui/async-await/drop-option-future.rs
error[E0597]: `value` does not live long enough
  --> tests/ui/async-await/drop-option-future.rs:12:22
   |
12 |     f = Some(async { value });
   |                    --^^^^^--
   |                    | |
   |                    | borrowed value does not live long enough
   |                    value captured here by generator
13 |     core::mem::drop(f);
14 | }
   | -
   | |
   | `value` dropped here while still borrowed
   | borrow might be used here, when `f` is dropped and runs the destructor for type `Option<impl Future<Output = i32>>`

The fix 9f36f98 does not appear to affect or include a regression test for the #98077 case, so let's add that test.

Closes #98077 since we add the test from that issue.

[rustbot]

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[mati865]

@bors r+

[rust-bors]

📌 Commit e897b4e has been approved by mati865

It is now in the queue for this repository.