RFR[12] JDK-8211978: move testlibrary/jdk/testlibrary/SimpleSSLContext.java and testkeys to network testlibrary

[sha.jiang at oracle.com]

Hi,
This patch moves 
test/jdk/lib/testlibrary/jdk/testlibrary/SimpleSSLContext.java to 
test/lib/jdk/test/lib/net/SimpleSSLContext.java.

Webrev: http://cr.openjdk.java.net/~jjiang/8211978/webrev.00/
Issue: https://bugs.openjdk.java.net/browse/JDK-8211978

Best regards,
John Jiang