RFR: 8342997: Remove use of System::getSecurityManager and SecurityManager [v2]

[Kevin Rushforth]

On Wed, 13 Nov 2024 13:33:06 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> Ths PR removes all remaining calls to `System::getSecurityManager` and the `SecurityManager` class along with the `System.getGecurityManager() != null` code paths.
>> 
>> As part of doing this, the last uses of `PermissionHelper` and `FXPermissions` were eliminated, so I deleted those two classes. Since `PermissionHelper` was the last remaining use of `AccessControlException`, I am adding JDK-8342998 to this PR.
>> 
>> In a few places, I noted some "check permissions" methods that are now no-ops that might be candidates for further cleanup (not directly related, so not planned for jfx24).
>> 
>> Finally, I deleted several unused methods in `MethodUtil` and `ReflectUtil` (some of these were already removed in the corresponding JDK classes, and some of them were unused after the changes to remove the call to `getSecurityManager`).
>
> Kevin Rushforth has updated the pull request incrementally with three additional commits since the last revision:
> 
>  - Replace 'TODO: SM removal:' comments with 'TODO: JDK-nnnnnnn:'
>  - Additional cleanup of unused fields, imports, and comments related to permissions
>  - Review comments: remove unused field, methods in FXMLLoader

In addition to the suggested changes, I did one more pass looking for unused fields, imports, and comments related to permissions.

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PR Review: https://git.openjdk.org/jfx/pull/1631#pullrequestreview-2429805137