It is tricky to create EC_FELEMs right now. This will simplify making them. Change-Id: Icde518efed61381004e2e5569a45d653af48ca2a Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/40585 Commit-Queue: David Benjamin <davidben@google.com> Reviewed-by: Adam Langley <agl@google.com>