Inbound streaming does not handle Symmetric Holder-Of-Key correctly

The streaming code has a problem when processing a request which contains a Holder-of-key SAML Assertion with a Subject which has an EncryptedKey in the KeyInfo, and a Signature in the security header which uses HMAC + points to the SAML Assertion.

The following code in SecurityTokenFactoryImpl:

if (keyInfoType != null) {
final SecurityTokenReferenceType securityTokenReferenceType
= XMLSecurityUtils.getQNameType(keyInfoType.getContent(), WSSConstants.TAG_wsse_SecurityTokenReference);

... bypasses the EncryptedKey, and instead only returns a SecurityToken of the (encrypting) certificate. Instead it should detect that the immediate child of KeyInfo is an EncryptedKey + process this accordingly.