[16] RFR JDK-8172366: Support SHA-3 based signatures

[Valerie Peng]

Can someone help review this SHA-3 based signature support? Note that 
changes to SunPKCS11 provider will be covered by a separate RFE 
(JDK-8244154). Current webrev adds SHA-3 digest support to DSA, RSA, 
ECDSA signature algorithms. I am a bit on the fence for the DSA 
signature and am including it here mostly for completeness sake. Can 
remove it if that's preferred. Comments?

Will file a CSR for this once we reached consensus on whether to add 
SHA-3 support to DSA signature.

RFE: https://bugs.openjdk.java.net/browse/JDK-8172366

Webrev: http://cr.openjdk.java.net/~valeriep/8172366/webrev.00/

Thanks,
Valerie