[8u] RFR Backport 8177334: Update xmldsig implementation to Apache Santuario 2.1.1

[Elliott Baron]

On 2020-06-17 5:22 p.m., Elliott Baron wrote:
>>
>> My main concern is that, although we don't add the new algorithms to
>> DigestMethod & SignatureMethod, or their tests, we do seem to be adding
>> support in e.g. JCEMapper for new algorithms like SHA3. I think we
>> should be consistent here and if we're not going to put new algorithms
>> in DigestMethod & SignatureMethod, and not include tests of them, they
>> shouldn't be being implemented.
> 
> Makes sense to me. I've removed the code related to SHA-3 algorithms, 
> and also Whirlpool, which also seems to not be unimplemented.

*seems to be unimplemented.