The unit test helper function LoadWithAllowedSchemes should
only be used to load a Cast Certificate. So it has been
renamed to make that clear.
The only unit test that used the old function with the
non-cast padding scheme has been removed. A replacement will
be added in the next CL of the chain.
Change-Id: Id4aa2f420435baff664324ee4b3dcb74ab9ffe8a
e0d30c5fc0