external/bouncycastle: Upgrade to version 1.57

Merge remote-tracking branch 'aosp/upstream-master' into merge-157

Notable changes or modifications beyond a simple merge:
* Omitted a lot of new code that's unnecessary for us
* Commented out new algorithm support, mostly ARIA and GM
* Default DSA key size returned to 1024
* Restored org.bouncycastle.asn1.pkcs.Attribute, it was removed
  previously but modifications to code we use need it

This change integrates a change from Bouncy Castle that increases the
default key size for DH from 1024 to 2048, which seems like a good
idea because 1024-bit keys are at the end of acceptable security at this
point.  This shouldn't be a problem for apps, because this only affects
the default (so anyone who cares can specify a key size) and only
affects creating new keys.

Test: cts -m CtsLibcoreTestCases
Test: cts -m CtsLibcoreFileIOTestCases
Test: cts -m CtsLibcoreJsr166TestCases
Test: cts -m CtsLibcoreOjTestCases
Test: cts -m CtsLibcoreOkHttpTestCases
Test: cts -m CtsLibcoreWycheproofBCTestCases
Bug: 38331562
Bug: 31801320
Change-Id: I56d1945b565f568c699edc36881e502cab855ddf