crypto/sha3: Copy latest code from "golang.org/x/crypto/sha3"

crypto/sha3/LICENSE

crypto/sha3/PATENTS

crypto/sha3/doc.go

crypto/sha3/hashes.go

crypto/sha3/keccakf.go

crypto/sha3/register.go

crypto/sha3/sha3.go

crypto/sha3/sha3_test.go

crypto/sha3/shake.go

crypto/sha3/testdata/keccakKats.json.deflate

crypto/sha3/xor.go

crypto/sha3/xor_generic.go

crypto/sha3/xor_unaligned.go