Using a different SP entity ID with the IdP SAML authn flow

[Cantor, Scott]

Many times when this runs, it will not find any of those contexts. On top of that, when it runs inside the SAML proxying flow, it's going to be a much more complex tree, and the input PRC is a nested one that's going to be literally below the AuthenticationContext as a child.

Try checking if the input PRC has a parent. If not, return the default. If it does, walk up via getParent, and that should be the AuthenticationContext to operate from.

-- Scott