bug#38813: Make comint-tests more robust

[Michael Albinus]

Mattias Engdegård <mattiase@acm.org> writes:

> There seem to be races in the new comint-tests; they frequently hang
> and/or fail when run (make check) on macOS.
> This patch should improve matters. OK for emacs-27?

> -            (accept-process-output proc 0 1 t)
> +            (accept-process-output proc 0 100 t)
> +            (accept-process-output proc 0 100 t)

The usual pattern is (while (accept-process-output proc 0 nil t))
That's what I do in tramp-tests.el

Best regards, Michael.