cuda_canny : multi stream safety (#11483)

* CUDA_ImgProc/Canny Asynchronous test

* cuda_canny : multi stream safety (1/3)

- Convert global variable canny::counter to class local variable

* cuda_canny : multi stream safety (2/3)

- Use texture objects rather than texture reference for cc >= 3.0,
  since texture reference must be declared as a static global variable
  which results in race condition when ran concurrently

* cuda_canny : multi stream safety (3/3)

- Refrain from using global variable in row_filter and column_filter
  (converts column_filter::c_kernel and row_filter::c_kernel to local
  variables)

* Fixes #11193

with the ffmpeg backend

  * remove meaningless tests

* add v_float64x2 support to v_rotate_*
* treat float vector in v_check_any, vec_any_lt as int vector
* add test case for v_rotate_left

* FIX INF_ENGINE RELU ERROR

* set slope to variable

* tab in indentwq

modules\dnn\src\layers\prior_box_layer.cpp(208): warning C4834: discarding return value of function with 'nodiscard' attribute

* Resolves 6125

* Fix test code

* Delete unnecessary code

to avoid accessing of 'p[-1]' (static code analysers dislike this)

Arm: fix the test failure of OCL_Imgproc/CLAHETest.Accuracy on ODROID-XU4 (#11409)

* fix the test failure of OCL_Imgproc/CLAHETest.Accuracy on ODROID-XU4
  * avoid the race condition in the reduce

* imgproc(ocl): simplify CLAHE code

* remove unused class

OpenCV 3.4.1 for Intel Computer Vision SDK

for cv::Mat with type=16UC3 and width < 16

std::exception_ptr requires enabled C++11 mode

- remove duplicates
- restore "always on" missing entries
- fix FP16 detection on MSVC