Remove crypto tests that have been moved to Conscrypt.

The latest sync of Conscrypt includes external copies of many of the
crypto tests in libcore, so delete the copies of those tests in
libcore as they're now redundant.  The test cases left in CipherTest
are only those that test the behavior of the library classes
themselves or the provider infrastructure in Android, rather than the
behavior of the security provider that provides the implementation.

Bug: 65476203
Test: cts -m CtsLibcoreTestCases
Change-Id: I0cfd83b3dabd536158bddd4e02a4cf709aa212ea