external/conscrypt: support arbitrary ECC groups.

The Java provider mechanism doesn't really let us fallback to another
provider based on whether certain ECC groups are supported or not. Since
I expect that some people will be trying to do Bitcoin on Android, this
should keep them happy.

Change-Id: I1db48b104e12a6e7dae21df9c31c21bff0d62a9b
3 files changed