test-xalloc-die: avoid unwarranted test failure on OpenSolaris 5.11

test-xalloc-die: avoid unwarranted test failure on OpenSolaris 5.11

* tests/test-xalloc-die.sh: Redirect stdout before stderr, (i.e.,
"> out 2> err", rather than "2> err > out").  Otherwise, with /bin/sh
on OpenSolaris 5.11 snv_134, we would end up with a stray "1> out"
line in the "err2" output file when running "make check" in verbose
mode (i.e., with set -x enabled).