tests: Do not test DRBG_REINIT from "make check"
* tests/random.c (main): Run check_drbg_reinit only if the envvar GCRYPT_IN_REGRESSION_TEST is set.
Without a hardware entropy generator (e.g. the moonbase token) running
the regression suite would take too long. We better use a set of test
vectors when run from "make check".
- Signed-off-by: Werner Koch <wk@gnupg.org>