bug#65590: 29.0.50; esh-var-test/interp-concat-cmd fails on macOS

[Stefan Kangas]

Jim Porter <jporterbugs@gmail.com> writes:

> This looks like a race condition when executing this command:
>
>    echo ${*echo "foo\nbar"}-baz
>
> That *should* print "foo\nbar-baz", but it tries to print "-baz" (and
> fails). That appears to be because the subcommand (*echo "foo\nbar")
> produces no output.

I can confirm that the error is intermittent, as I'm not seeing it on a re-run.