remove SecurityManager references

[gurunrao]

remove SecurityManager references as per JEP 486 [ link - https://openjdk.org/jeps/486 ].

Important points captured from JEP 486 [ https://openjdk.org/jeps/486 ] for JDK24 + Security manager codes:

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In JDK 24, where a Security Manager is never enabled, the System::getSecurityManager and AccessController::doPrivileged methods behave as they did in JDK 17 when a Security Manager was not enabled,

System::getSecurityManager returns null,
The SecurityManager::check* methods throw SecurityException, and
The six AccessController::doPrivileged methods execute the given action immediately.

Rendering the Security Manager API non-functional

The Security Manager API consists of:

Methods in the java.lang.SecurityManager class,
Methods in the AccessController, AccessControlContext, Policy, and ProtectionDomain classes of the java.security package, and
The getSecurityManager and setSecurityManager methods in the java.lang.System class.

We are not removing these methods from Java 24; rather, we are changing them to have no effect. They will, as appropriate, return null or false, or pass through the caller's request, or unconditionally throw a SecurityException.

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