Moved test requiring VSPremium to separate test proj.
- Created a separate solution for VSPremium that also includes the new premium test proj.
- Moved Saml2Response_Validate_FalseOnMissingReference to the new test proj.
- Set up a separate project for shared test functionality.
Removed shim creation warning.
- Only create shim for the single type that actually needs it.
Renamed tests for references in signatures
- Added InSignature to Saml2Response_Validate_FalseOnDualReferencesInSignature
- Added InSignature to Saml2Response_Validate_FalseOnMissingReferenceInSignature test.