Fix ability to compile tests without -DVERIFY.
Fix ability to compile tests without -DVERIFY.

Broken by 3f3964e4.

It's important that the tests are also run without -DVERIFY due to
 the possibility that side-effects of a VERIFY_CHECK fix a bug that
 would otherwise be detected.

Use of the verify_check macro in tests isn't sufficient.

libbitcoin/secp256k1,afk11/secp256k1,evoskuil/secp256k1,afk11/secp256k1,bitcoin-core/secp256k1,bitcoin/secp256k1,libbitcoin/secp256k1,ElementsProject/secp256k1-zkp,afk11/secp256k1,evoskuil/secp256k1,evoskuil/secp256k1,pmienk/secp256k1,pmienk/secp256k1,bitcoin/secp256k1,peterdettman/secp256k1,pmienk/secp256k1,libbitcoin/secp256k1,pmienk/secp256k1,afk11/secp256k1,ElementsProject/secp256k1-zkp,bitcoin/secp256k1,libbitcoin/secp256k1,afk11/secp256k1,bitcoin/secp256k1,libbitcoin/secp256k1,peterdettman/secp256k1,pmienk/secp256k1,evoskuil/secp256k1,bitcoin-core/secp256k1,evoskuil/secp256k1,bitcoin/secp256k1