test_follow_name_truncate2 intermittent failure

 ---- test_tail::test_follow_name_truncate2 stdout ----
bin: "/Users/runner/work/coreutils/coreutils/target/x86_64-apple-darwin/debug/coreutils"
touch: /var/folders/8j/sfr9qqcj73j4p6nhwcfpr0th0000gn/T/.tmpcWgfuY/file
run: /Users/runner/work/coreutils/coreutils/target/x86_64-apple-darwin/debug/coreutils tail --follow=name file
write(append): /var/folders/8j/sfr9qqcj73j4p6nhwcfpr0th0000gn/T/.tmpcWgfuY/file
write(append): /var/folders/8j/sfr9qqcj73j4p6nhwcfpr0th0000gn/T/.tmpcWgfuY/file
write(append): /var/folders/8j/sfr9qqcj73j4p6nhwcfpr0th0000gn/T/.tmpcWgfuY/file
write(truncate): /var/folders/8j/sfr9qqcj73j4p6nhwcfpr0th0000gn/T/.tmpcWgfuY/file

thread 'test_tail::test_follow_name_truncate2' panicked at tests/by-util/test_tail.rs:2135:10:
assertion failed: `(left == right)`

Diff < left / right > :
 x
 x
 x
>x
 
error: test failed, to rerun pass `-p coreutils --test tests`


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_is
             at ./tests/uutests/src/lib/util.rs:540:9
   3: tests::test_tail::test_follow_name_truncate2
             at ./tests/by-util/test_tail.rs:2131:5
   4: tests::test_tail::test_follow_name_truncate2::{{closure}}
             at ./tests/by-util/test_tail.rs:2097:32
   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.

https://github.com/uutils/coreutils/actions/runs/30299617640/job/90090129647?pr=12333

Start with tests/by-util/test_tail.rs around test_follow_name_truncate2, especially the assertion at line 2135, and rerun the test using the command from the failure report. Investigate why the intermittent tail --follow=name sequence produces an extra x after truncation. Done means the test is reliable and its expected output matches the intended behavior.