test_separator_attached_equals_multi_char intermittent failure #14244

---- test_sort::test_separator_attached_equals_multi_char stdout ----
bin: "/target/x86_64-unknown-linux-gnu/debug/coreutils"
run: /target/x86_64-unknown-linux-gnu/debug/coreutils sort -t=a -k 2

thread 'test_sort::test_separator_attached_equals_multi_char' panicked at tests/uutests/src/lib/util.rs:2894:18:
called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: "failed to write to stdin of child: Broken pipe (os error 32)" }
stack backtrace:
   0: __rustc::rust_begin_unwind
             at /rustc/6b00bc3880198600130e1cf62b8f8a93494488cc/library/std/src/panicking.rs:697:5
   1: core::panicking::panic_fmt
             at /rustc/6b00bc3880198600130e1cf62b8f8a93494488cc/library/core/src/panicking.rs:75:14
   2: core::result::unwrap_failed
             at /rustc/6b00bc3880198600130e1cf62b8f8a93494488cc/library/core/src/result.rs:1732:5
   3: core::result::Result<T,E>::unwrap
             at /rust/lib/rustlib/src/rust/library/core/src/result.rs:1137:23
   4: uutests::util::UChild::join
             at ./tests/uutests/src/lib/util.rs:2891:13
   5: uutests::util::UChild::wait_with_output
             at ./tests/uutests/src/lib/util.rs:2610:9
   6: uutests::util::UChild::wait
             at ./tests/uutests/src/lib/util.rs:2585:22
   7: uutests::util::UCommand::run
             at ./tests/uutests/src/lib/util.rs:2096:9
   8: uutests::util::UCommand::fails
             at ./tests/uutests/src/lib/util.rs:2120:26
   9: tests::test_sort::test_separator_attached_equals_multi_char
             at ./tests/by-util/test_sort.rs:1831:5
  10: tests::test_sort::test_separator_attached_equals_multi_char::{{closure}}
             at ./tests/by-util/test_sort.rs:1829:47
  11: core::ops::function::FnOnce::call_once
             at /rust/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
  12: core::ops::function::FnOnce::call_once
             at /rustc/6b00bc3880198600130e1cf62b8f8a93494488cc/library/core/src/ops/function.rs:250:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.