libminijail_unittests: add more for consume*
libminijail_unittests: add more for consume*

consume* lack unittests. This adds some.

TEST=run unittests
BUG=none

Change-Id: I52a63040a4cc5b21eae4a8ab5447dc225c855b56
Reviewed-on: https://gerrit.chromium.org/gerrit/10541
Commit-Ready: Will Drewry <72416dde44ea762d19e3a7a555e3b59ce98f8eea@chromium.org>
Reviewed-by: Will Drewry <72416dde44ea762d19e3a7a555e3b59ce98f8eea@chromium.org>
Tested-by: Will Drewry <72416dde44ea762d19e3a7a555e3b59ce98f8eea@chromium.org>

omegaup/minijail,omegaup/minijail,omegaup/minijail,omegaup/minijail