VMS: modernise rand_pool_acquire_entropy, step 2
VMS: modernise rand_pool_acquire_entropy, step 2

Add more items that could serve as entropy source.

Reviewed-by: Andy Polyakov <015edf36635e030d5e009e08808a59984e629740@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6151)

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl