Test pipeline support for off heap disabled testing

With Off-Heap Technology for Large Arrays in GC ([top-level off-heap issue](https://github.com/eclipse-openj9/openj9/issues/14005)), we need to add the test pipeline support for off-heap enabled/disabled testing. The two proposed options to enable(will be default)/disable off-heap are -XXgc:enableVirtualLargeObjectHeap / -XXgc:disableVirtualLargeObjectHeap (should be introduced in https://github.com/eclipse-openj9/openj9/pull/14667)

Off-heap is enabled by default, which means off-heap enabled will be tested in the existing test pipeline. We may add additional tests for off-heap enabled. We also need to cover off-heap disabled testing. The focus is JDK21 for now. And off-heap disabled testing should be run for a relatively short term (~6mths) until the feature is stable.

**Details**:
Find all tests that run Balanced GC policy (i.e., -Xgcpolicy:balanced) and add additional variation with ` -XXgc:disableVirtualLargeObjectHeap`.

For example: https://github.com/adoptium/aqa-tests/blob/d4e891679b27e9248405eb40397c178f4e985c52/functional/SyntheticGCWorkload/playlist.xml#L175
and tests use mode that contains ` -Xgcpolicy:balanced` in https://github.com/adoptium/TKG/blob/master/resources/modes.xml

FYI @dmitripivkine @pshipton @renfeiw

Start by searching for -Xgcpolicy:balanced in TKG resources/modes.xml and the referenced AQA tests, including functional/SyntheticGCWorkload/playlist.xml. Identify every Balanced GC test variation for JDK21, then add coverage using -XXgc:disableVirtualLargeObjectHeap alongside the existing default-enabled runs. Done means the disabled configuration runs through the test pipeline for all identified cases.

Written by the indexing model from the issue text.