RFR: 8168078: Remove permission to read all system properties granted to the jdk.crypto.ec module

[Sean Mullan]

Please review this fix to remove granting the unnecessary 
PropertyPermission to the jdk.crypto.ec module:

http://cr.openjdk.java.net/~mullan/webrevs/8168078/webrev.00/
The existing TestEC test has been modified to also run under a 
SecurityManager to verify that removing the permission does not break 
anything.

--Sean