crypto: Add SHA3 functions in go.crypto/sha3 to the Hash enum.
crypto: Add SHA3 functions in go.crypto/sha3 to the Hash enum.

Reverse dependency of https://codereview.appspot.com/130950043/

LGTM=agl
R=golang-codereviews, agl
CC=agl, golang-codereviews
https://codereview.appspot.com/138800043

Committer: Adam Langley <db68fba232b2c49ed3e9d3081df349dde7b61dfd@golang.org>

sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,webfd/go-zh,d0f/go-zh,sanjosh/sanjos100-tipc,webfd/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,d0f/go-zh,sanjosh/sanjos100-tipc,bryanxu/go-zh,webfd/go-zh,webfd/go-zh,d0f/go-zh,webfd/go-zh,sanjosh/sanjos100-tipc,bryanxu/go-zh,bryanxu/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,webfd/go-zh,webfd/go-zh,bryanxu/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,d0f/go-zh,bryanxu/go-zh,bryanxu/go-zh,bryanxu/go-zh,webfd/go-zh,bryanxu/go-zh,d0f/go-zh