Auto merge of #112314 - ferrocene:pa-core-alloc-abort, r=bjorn3

Ignore `core`, `alloc` and `test` tests that require unwinding on `-C panic=abort`

Some of the tests for `core` and `alloc` require unwinding through their use of `catch_unwind`. These tests fail when testing using `-C panic=abort` (in my case through a target without unwinding support, and `-Z panic-abort-tests`), while they should be ignored as they don't indicate a failure.

This PR marks all of these tests with this attribute:

```rust
#[cfg_attr(not(panic = "unwind"), ignore = "test requires unwinding support")]
```

I'm not aware of a way to test this on rust-lang/rust's CI, as we don't test any target with `-C panic=abort`, but I tested this locally on a Ferrocene target and it does indeed make the test suite pass.

Author: bors