Rollup merge of #97970 - dtolnay:terminate, r=joshtriplett

Fix Termination impl panic on closed stderr

Repro:

```rust
#![feature(backtrace)]

use std::backtrace::Backtrace;
use std::io::{self, Write as _};
use std::panic::{self, PanicInfo};

#[derive(Debug)]
pub struct Error;

fn panic_hook(panic_info: &PanicInfo) {
    let backtrace = Backtrace::force_capture();
    let _ = write!(io::stdout(), "{}\n{}", panic_info, backtrace);
}

fn main() -> Result<(), Error> {
    panic::set_hook(Box::new(panic_hook));
    let stderr = io::stderr();
    let mut stderr = stderr.lock();
    while stderr.write_all(b".\n").is_ok() {}
    Err(Error)
}
```

### Before:

```console
$ target/debug/repro 3>&2 2>&1 1>&3 | head
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panicked at 'failed printing to stderr: Broken pipe (os error 32)', library/std/src/io/stdio.rs:1016:9
   0: testing::panic_hook
             at ./src/main.rs:11:21
   1: core::ops::function::Fn::call
             at /git/rust/library/core/src/ops/function.rs:77:5
   2: std::panicking::rust_panic_with_hook
   3: std::panicking::begin_panic_handler::{{closure}}
   4: std::sys_common::backtrace::__rust_end_short_backtrace
   5: rust_begin_unwind
   6: core::panicking::panic_fmt
   7: std::io::stdio::_eprint
   8: <core::result::Result<!,E> as std::process::Termination>::report
             at /git/rust/library/std/src/process.rs:2164:9
   9: <core::result::Result<(),E> as std::process::Termination>::report
             at /git/rust/library/std/src/process.rs:2148:25
  10: std::rt::lang_start::{{closure}}
             at /git/rust/library/std/src/rt.rs:145:18
  11: std::rt::lang_start_internal
  12: std::rt::lang_start
             at /git/rust/library/std/src/rt.rs:144:17
  13: main
  14: __libc_start_main
             at /build/glibc-SzIz7B/glibc-2.31/csu/../csu/libc-start.c:308:16
  15: _start
```

### After:

```console
$ target/debug/repro 3>&2 2>&1 1>&3 | head
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```

std/src/process.rs

@@ -2161,7 +2161,9 @@ impl Termination for ! {
 impl<E: fmt::Debug> Termination for Result<!, E> {
     fn report(self) -> ExitCode {
         let Err(err) = self;
-        eprintln!("Error: {err:?}");
+        // Ignore error if the write fails, for example because stderr is
+        // already closed. There is not much point panicking at this point.
+        let _ = writeln!(io::stderr(), "Error: {err:?}");
         ExitCode::FAILURE
     }
 }