Add a test to show the incorrect ASN1 conversion to and from points.
This was due to the check if Y is odd/even being inverted which
incorrectly prefixes the X coordinate with the wrong byte.
The test itself was not fully correct because it was using compliant
points rather than full points, and the spec contains the entire
Y coordinate so the full point should be used.
This patch also adds ASN1 conversions to validate that
dpp_point_from_asn1 and dpp_point_to_asn1 work properly.
James Prestwood