Review Request: 8130007: Update security tests to use Security.getProvider to get security provider

[Mandy Chung]

http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8130007/webrev.00/

This patch removes the use of internal API and use Security.getProvider where appropriate.   Valerie and I both contributes to this patch.

Mandy