tests: Tolerate ignored SIGPIPE in daemon tests.

tests: Tolerate ignored SIGPIPE in daemon tests.

I noticed that when I run "make check" inside an Emacs compile-mode buffer,
the "daemon --detach closes standard fds" and "daemon --detach --monitor closes
standard fds" tests failed.  Investigation showed that Emacs ignores
SIGPIPE in the compile subprocess, which caused the "yes" process in these
tests to emit the message "yes: Broken pipe" and exit with status 1 instead
of dying from SIGPIPE.

This commit changes these tests to allow either behavior.