Construct SCT from base64 in ct_test
Construct SCT from base64 in ct_test

This gives better code coverage and is more representative of how a
user would likely construct an SCT (using the base64 returned by a CT log).

Reviewed-by: Tim Hudson <eb0be8e447f673b41b10eda09d63cd72526b0a42@openssl.org>
Reviewed-by: Rich Salz <c04971a99e5a9ee80eaab4b1deb37e845b0bd697@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1548)
openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl