sun.security.x509: port change rev/d1c04dac850d

The change rev/d1c04dac850d addresses the case of the string
"CN=prefix\\<>suffix", which should throw an InvalidArgumentException
when constructing a X500Principal, and doesn't throw before this change.
Also, characters after '<' are ignored. We have tests documenting that
we allow such strings, like X500PrincipalTest#testIllegalInputName_07,
so in this change we modify rev/d1c04dac850d as to allow the string. We
check that the characters after '<' are not ignored. X500PrincipalTest
thoroughly tests the code in AVA.java .

There was some generics tidying in X500Name, and also some added
whitespace that we keep in order to minimize differences with upstream.

Change-Id: I2ca8db5beeb53cdcd1f8a3e7abd91d11ba20103c
Test: run CtsLibcoreTestCases , the code is specifically tested in X500PrincipalTest
Bug: 29631070