RFR: 8232066: Remove outdated code/methods from PKIX implementation

[Weijun Wang]

On Thu, 29 Jul 2021 14:24:52 GMT, Sean Mullan <mullan at openjdk.org> wrote:

> Please review this fix to remove the Validator.VAR_PLUGIN_CODE_SIGNING variant and related code that is no longer needed in the PKIX implementation.

Looks good. One nit: `Validator::getInstance` methods are internal. Does it really matter to check for null?

-------------

Marked as reviewed by weijun (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4934