There seems to be an issue with i2d_provided() in i2d_evp.c that causes
us to fail to construct a valid chain of encoders for the "type-specific"
output when it's an EC pubkey. This test is designed to exercise that
codepath for a variety of curves.
Reviewed-by: Tomas Mraz <tomas@openssl.org> Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14291)