* added paddle.polar to paddle

* added paddle.polar unitest

* failed to use pytorch for evaluating results, and changed with numpy implementation

* updated code style

* updated __init__.py

* updated code style

* fixed unitest code

* lkh test polar

* polar add

* fixed errors and optimized code

* fixed error

* optimized polor api

* updated code style

* updated code style

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Co-authored-by: Ndiadestiny <1247889154@qq.com>