Use T as temp var type in polyanticlockwise()

[y-guyon]

To match the input data type.
Cast inner computation to double to prevent int overflows for any input type.

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work (the input image triggering the overflow is not publicly available)
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake

[asmorkalov]

@y-guyon please take a look on CI. The patch breaks build.

[y-guyon]

@y-guyon please take a look on CI. The patch breaks build.

Yes thanks, I received the GitHub notification by email.
I moved the definitions to the .cc file now that they are not templated anymore.

[asmorkalov]

👍