backport 997b7b18

add messages to avoid silent kernel destruction

Fix a bug in cv :: merge when array of 3-channel mat is input (#13544)

* Mat merge function bug fix - Bug fix of merge function of 3-channel vector <Mat> of 3 or 4 matrices

* Add Core_merge test for opencv#13544

* fixups

used by OpenCV

* Added performance tests for hal::norm functions

* Added sum of absolute differences intrinsic

* norm implementation updated to use wide universal intrinsics

* improve and fix v_reduce_sad on VSX

created from RAW memory buffers (without proper lifetime management)

introduced by commit 4e629000

  - add infrastructure support for Power9/VSX3
  - fix missing VSX flags on GCC4.9 and CLANG4(#13210, #13222)
  - fix disable VSX optimzation on GCC by using flag ENABLE_VSX
  - flag ENABLE_VSX is deprecated now, use CPU_BASELINE, CPU_DISPATCH instead
  - add VSX3 to arithmetic dispatchable flags

* significantly reduced OpenCV binary size by disabling IPP calls in some OpenCV functions: Sobel, Scharr, medianBlur, GaussianBlur, filter2D, mean, meanStdDev, norm, sum, minMaxIdx, sort.

* re-enable IPP in norm, since it's much faster (without adding too much space overhead)

This reverts commit 7349b8f5 (partially).

* integrated the new C++ persistence; removed old persistence; most of OpenCV compiles fine! the tests have not been run yet

* fixed multiple bugs in the new C++ persistence

* fixed raw size of the parsed empty sequences

* [temporarily] excluded obsolete applications traincascade and createsamples from build

* fixed several compiler warnings and multiple test failures

* undo changes in cocoa window rendering (that was fixed in another PR)

* fixed more compile warnings and the remaining test failures (hopefully)

* trying to fix the last little warning