RFR: 8342993: Remove uses of AccessController and AccessControlContext from JavaFX

[Kevin Rushforth]

On Thu, 14 Nov 2024 20:59:16 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

> This PR removes all remaining uses of `AccessController` and `AccessControlContext`, which represent the last remaining uses of the terminally deprecated security APIs except for those in the `/ios/` or `/android/` directories.
> 
> With the removal of doPrivileged and the `if (System.getSecurityManager() != null)` code paths, the ACC is no longer used, so can be completely eliminated. Along with this, I removed all unused imports of security-related APIs and all related `@SuppressWarnings("removal") annotations.
> 
> ### Notes to reviewers
> 
> * Most of the changes were straight-forward removals of methods and fields to save, retrieve and pass around the `AccessControlContext`.
> * The Toolkit class stores a collection of listeners in a `WeakHashMap` with the listener as the key (thus weakly held) and the ACC as the value. We no longer need or want the ACC, but I kept the use of `WeakHashMap` and changed the value type to `Object`, storing a singleton dummy object as the value for each entry. This minimizes the changes, while preserving the behavior of reclaiming the entries when they are garbage collected.

Reviewers: @arapte @andy-goryachev-oracle

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PR Comment: https://git.openjdk.org/jfx/pull/1638#issuecomment-2477540942