[8u] RFR 8141457: keytool default cert fingerprint algorithm should be SHA-256

[Zhengyu Gu]

I would like to backport this to 8u for parity with Oracle 8u271.

The original patch does not apply cleanly.

There are a couple of minor conflicts with Main.java and Resource.java, 
which are easy to resolve.

Patches to following files, apparently already came in via JDK-8048830

api_cert_chain.p12_expected.data
api_private_key.p12_expected.data
api_private_key_not_match.p12_expected.data
api_two_pass.p12_expected.data


Original bug: https://bugs.openjdk.java.net/browse/JDK-8141457
Original patch: http://hg.openjdk.java.net/jdk9/jdk9/jdk/rev/97b25277c28f

8u webrev: http://cr.openjdk.java.net/~zgu/JDK-8141457-8u/webrev.00/

Test:
   jdk_security


Thanks,

-Zhengyu