[Fix] Optimize preprocess & fix pontential use-after-free

[lzhangzz]

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Modification

• keep a copy of intermediate Tensor/Mat if possible.
• otherwise insert a sync operation to avoid use-after-free
• replace per-transformation sync with a final sync in Compose

BC-breaking (Optional)

None (hopefully)

Use cases (Optional)

If this PR introduces a new feature, it is better to list some use cases here, and update the documentation.

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit tests to ensure the correctness.
3. If the modification has a dependency on downstream projects of a newer version, this PR should be tested with all supported versions of downstream projects.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[codecov]

Codecov Report

Merging #229 (6c356c0) into master (6948e3d) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

❗ Current head 6c356c0 differs from pull request most recent head 2c64e51. Consider uploading reports for the commit 2c64e51 to get more accurate results

@@            Coverage Diff             @@
##           master     #229      +/-   ##
==========================================
- Coverage   66.83%   66.82%   -0.02%     
==========================================
  Files         190      190              
  Lines        6292     6293       +1     
  Branches      981      981              
==========================================
  Hits         4205     4205              
- Misses       1778     1779       +1     
  Partials      309      309              

Flag	Coverage Δ
unittests	66.82% <0.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmdeploy/backend/sdk/wrapper.py	0.00% <0.00%> (ø)

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[irexyc]

LGTM

[lvhan028]

Please merge to master branch, and add SyncOnScopeExit for DefaultFormatBundle

[lvhan028]

LGTM