Change Details

* Added test with additions resulting in infinity * Clear field elements when writing infinity This is a backport of secp256k1 PR699

* Added test with additions resulting in infinity * Clear field elements when writing infinity This is a backport of secp256k1 [[https://github.com/bitcoin-core/secp256k1/pull/699 | PR699]]

* Added test with additions resulting in infinity * Clear field elements when writing infinity This is a backport of secp256k1 [[https://github.com/bitcoin-core/secp256k1/pull/699 | PR699]]