evp_test: add a new global "Test-Entropy" line to allow deterministic `random` input.

evp_test: add a new global "Test-Entropy" line to allow deterministic `random` input.

When specified, this directive replaces the public and private DRBGs
with a generator that returns the specified bytes.  If more bytes are
requested than are specified, the generator loops around the supplied
bytes to satisfy the request.

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/27997)