Apply merge and split function for mp_reshard

[fjjF77]

PR types

Bug fixes

PR changes

APIs

Description

在mp_reshard中使用merge和split相关函数对tensor进行张量并行度的切换操作，支持reshard对于sequence_parallel，fuse_attention_qkv等的支持。

[paddle-bot]

Thanks for your contribution!

[codecov]

Codecov Report

Attention: Patch coverage is 11.11111% with 40 lines in your changes missing coverage. Please review.

Project coverage is 46.90%. Comparing base (64afc81) to head (a08b925).
Report is 3 commits behind head on develop.

Files with missing lines	Patch %	Lines
paddlenlp/rl/utils/reshard_utils.py	0.00%	24 Missing ⚠️
paddlenlp/transformers/conversion_utils.py	31.25%	11 Missing ⚠️
paddlenlp/rl/utils/comm_utils.py	0.00%	2 Missing ⚠️
paddlenlp/trainer/unified_checkpoint/utils.py	0.00%	2 Missing ⚠️
...dlenlp/experimental/transformers/qwen2/modeling.py	0.00%	1 Missing ⚠️

❌ Your patch check has failed because the patch coverage (11.11%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.
❌ Your project check has failed because the head coverage (46.90%) is below the target coverage (58.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #10637      +/-   ##
===========================================
- Coverage    46.91%   46.90%   -0.02%     
===========================================
  Files          799      799              
  Lines       132460   132479      +19     
===========================================
- Hits         62148    62139       -9     
- Misses       70312    70340      +28     

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