NCCL EP zero copy additional support

[YangFei1990]

Description

Addition support for NCCL EP zero copy feature, including

• Expose user provided recv_topk_weights buffer
• Use symm memory pool to allocate symm buffer

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes