bin/51894: [PATCH] tests/lib/libc/ssp/h_read: various fixes

[yaneurabeya%gmail.com@localhost]

>Number:         51894
>Category:       bin
>Synopsis:       [PATCH] tests/lib/libc/ssp/h_read: various fixes
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jan 15 21:35:00 +0000 2017
>Originator:     Ngie Cooper
>Release:        7.0.2
>Organization:
>Environment:
n/a
>Description:
- Use /dev/zero (_PATH_DEVZERO) instead of using/mangling `0` (stdin) -- IIRC the reasoning for this was that the test helper was hanging periodically on an older version of FreeBSD or when run by itself.
- Check the results of open/read and abort if they fail (this will still trigger the ssp edgecases). This is being done to resolve issues pointed out by Coverity.
>How-To-Repeat:

>Fix: