Perform sanity checks on generated P256 points

adds a test to VtsRemotelyProvisionedComponentTests that generates 256
P256 keypairs and adds functionality that makes sure the points (public
keys) lie on the curve, are not infinity, and are not equal to the base
point (generator).

Test: atest VtsHalRemotelyProvisionedComponentTargetTest
Bug: 327026543
Change-Id: I4002b9e5ed5dbc366a14ff5c16e2c4cfd7d14485