[fix] MD-TRT: handle c10::Error in bind_nccl_comm() probe loop

[apbose]

In PyTorch >= 2.13, c10d::resolve_process_group() throws c10::Error when a group name is not registered (previously returned nullptr). The probe loop in bind_nccl_comm() had no try/catch, so it crashed on i=1 even when only group "0" existed, breaking the save→load path for distributed TRT engines.

Fix:

• Wrap resolve_process_group() in try/catch(c10::Error) with continue (not break) so gaps from new_group(use_local_synchronization=True) don't stop the probe from finding numeric groups beyond the gap.
• Apply the same treatment to the soft-return call site at the end of bind_nccl_comm() (group_name resolved but not yet registered).
• Correct and expand comments to document the PyTorch numeric naming scheme and the gap scenario.

Tests: add tests/py/dynamo/distributed/test_bind_nccl_probe.py with:

• TestBindNcclProbeDetection: single group auto-resolve, local_sync gap, multiple groups deferral
• TestBindNcclProbeBinding: explicit world pin, subgroup pin, auto-resolve
• TestBindNcclProbeE2E: full save→load cycle regression test

Description

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