tests: use macros.h in more places

tests: use macros.h in more places

Make the ASSERT macro a bit more reusable.

* tests/macros.h (ASSERT): Depend on ASSERT_STREAM.
(ASSERT_STREAM): Provide default of stderr.
* tests/test-dirent-safer.c: Include macros.h, using alternate
stream for assertions.
* tests/test-dup-safer.c: Likewise.
* tests/test-freopen-safer.c: Likewise.
* tests/test-getopt.c: Likewise.
* tests/test-openat-safer.c: Likewise.
* tests/test-pipe.c: Likewise.
* tests/test-popen-safer.c: Likewise.
* modules/dirent-safer-tests (Files): Include macros.h.
* modules/unistd-safer-tests (Files): Likewise.
* modules/freopen-safer-tests (Files): Likewise.
* modules/getopt-posix-tests (Files): Likewise.
* modules/openat-safer-tests (Files): Likewise.
* modules/pipe-tests (Files): Likewise.

Signed-off-by: Eric Blake <ebb9@byu.net>