Auto merge of #60026 - Aaron1011:feature/miri-unwind, r=RalfJung,oli-obk

Add hooks for Miri panic unwinding

This commits adds in some additional hooks to allow Miri to properly
handle panic unwinding. None of this should have any impact on CTFE mode

This supports https://github.com/rust-lang/miri/pull/693

src/libcore/intrinsics.rs

@@ -1348,6 +1348,11 @@ extern "rust-intrinsic" {
     /// See documentation of `<*const T>::offset_from` for details.
     #[cfg(not(bootstrap))]
     pub fn ptr_offset_from<T>(ptr: *const T, base: *const T) -> isize;
+
+    /// Internal hook used by Miri to implement unwinding.
+    /// Perma-unstable: do not use
+    #[cfg(not(bootstrap))]
+    pub fn miri_start_panic(data: *mut (dyn crate::any::Any + crate::marker::Send)) -> !;
 }
 
 // Some functions are defined here because they accidentally got made