Fix group-offloading bug (#13211)
* Implement synchronous onload for offloaded parameters
Add fallback synchronous onload for conditionally-executed modules.
* add test for new code path about group-offloading
* Update tests/hooks/test_group_offloading.py
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
* use unittest.skipIf and update the comment
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Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
