Add Generational ZGC

[henri-tremblay]

For all changes:

• [ x] Is there a JIRA ticket associated with this PR? Is it referenced in the commit message? GEODE-7483
• [x ] Has your PR been rebased against the latest commit within the target branch (typically develop)? Yes
• [ x] Is your initial contribution a single, squashed commit? Yes
• [ x] Does gradlew build run cleanly? Yes
• [ x] Have you written or updated unit tests to verify your changes? It's JVM dependent, so new unit tests

We probably should add GC permutations in gradle.yml.

• [ x] If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0? Nothing new

[JinwooHwang]

Initiating the checks for @henri-tremblay

[JinwooHwang]

This change adds support for identifying the "ZGC Old Generation" memory pool in the isTenured method, which enhances compatibility with generational ZGC. The update is concise, follows the existing pattern, and is clearly commented. This should help ensure accurate heap monitoring on JVMs using generational ZGC.

LGTM

• Clear and consistent addition.
• Improves support for more JVM configurations.
• No impact on existing logic.