FR-9 OpenAM-3263 prevent a xss exploit in the openid connect check session jsp

git-svn-id: https://svn.forgerock.org/openam/trunk/openam@7316 0f4defcf-c51a-4c67-9f44-6fb5eba73c5d
FR-10 OPENAM-3274 verify the signature of the JWT id token passed into the  check session endpoint.

git-svn-id: https://svn.forgerock.org/openam/trunk/openam@7317 0f4defcf-c51a-4c67-9f44-6fb5eba73c5d