test_terminate_child_on_receiving_terminate intermittent failure

[xtqqczze]

---- test_timeout::test_terminate_child_on_receiving_terminate stdout ----
bin: "/Users/runner/work/coreutils/coreutils/target/x86_64-apple-darwin/debug/coreutils"
run: /Users/runner/work/coreutils/coreutils/target/x86_64-apple-darwin/debug/coreutils timeout 10 sh -c trap 'echo child received TERM' TERM; sleep 5

thread 'test_timeout::test_terminate_child_on_receiving_terminate' panicked at tests/by-util/test_timeout.rs:229:10:
'' does not contain 'child received TERM'
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: uutests::util::CmdResult::stdout_contains
             at ./tests/uutests/src/lib/util.rs:768:9
   3: tests::test_timeout::test_terminate_child_on_receiving_terminate
             at ./tests/by-util/test_timeout.rs:224:5
   4: tests::test_timeout::test_terminate_child_on_receiving_terminate::{{closure}}
             at ./tests/by-util/test_timeout.rs:213:49
   5: core::ops::function::FnOnce::call_once
             at /rustc/6b00bc3880198600130e1cf62b8f8a93494488cc/library/core/src/ops/function.rs:250:5
   6: 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.

CICD / Build (macos-latest, x86_64-apple-darwin, feat_os_unix, true) (pull_request)

[xtqqczze]

@cakebaker could you add these issues to Fix intermittent issues?