Merge pull request #23980 from hanliutong:rewrite-core

Rewrite Universal Intrinsic code by using new API: Core module. #23980

The goal of this PR is to match and modify all SIMD code blocks guarded by `CV_SIMD` macro in the `opencv/modules/core` folder and rewrite them by using the new Universal Intrinsic API.

The patch is almost auto-generated by using the [rewriter](https://github.com/hanliutong/rewriter), related PR #23885.

Most of the files have been rewritten, but I marked this PR as draft because, the `CV_SIMD` macro also exists in the following files, and the reasons why they are not rewrited are:

1. ~~code design for fixed-size SIMD (v_int16x8, v_float32x4, etc.), need to manually rewrite.~~ Rewrited
- ./modules/core/src/stat.simd.hpp
- ./modules/core/src/matrix_transform.cpp
- ./modules/core/src/matmul.simd.hpp

2. Vector types are wrapped in other class/struct, that are not supported by the compiler in variable-length backends. Can not be rewrited directly.
- ./modules/core/src/mathfuncs_core.simd.hpp 
```cpp
struct v_atan_f32
{
    explicit v_atan_f32(const float& scale)
    {
...
    }

    v_float32 compute(const v_float32& y, const v_float32& x)
    {
...
    }

...
    v_float32 val90; // sizeless type can not used in a class
    v_float32 val180;
    v_float32 val360;
    v_float32 s;
};
```

3. The API interface does not support/does not match

- ./modules/core/src/norm.cpp 
Use `v_popcount`, ~~waiting for #23966~~ Fixed
- ./modules/core/src/has_non_zero.simd.hpp
Use illegal Universal Intrinsic API: For float type, there is no logical operation `|`. Further discussion needed

```cpp
/** @brief Bitwise OR

Only for integer types. */
template<typename _Tp, int n> CV_INLINE v_reg<_Tp, n> operator|(const v_reg<_Tp, n>& a, const v_reg<_Tp, n>& b);
template<typename _Tp, int n> CV_INLINE v_reg<_Tp, n>& operator|=(v_reg<_Tp, n>& a, const v_reg<_Tp, n>& b);
```

```cpp
#if CV_SIMD
    typedef v_float32 v_type;
    const v_type v_zero = vx_setzero_f32();
    constexpr const int unrollCount = 8;
    int step = v_type::nlanes * unrollCount;
    int len0 = len & -step;
    const float* srcSimdEnd = src+len0;

    int countSIMD = static_cast<int>((srcSimdEnd-src)/step);
    while(!res && countSIMD--)
    {
        v_type v0 = vx_load(src);
        src += v_type::nlanes;
        v_type v1 = vx_load(src);
        src += v_type::nlanes;
....
        src += v_type::nlanes;
        v0 |= v1; //Illegal ?
....
        //res = v_check_any(((v0 | v4) != v_zero));//beware : (NaN != 0) returns "false" since != is mapped to _CMP_NEQ_OQ and not _CMP_NEQ_UQ
        res = !v_check_all(((v0 | v4) == v_zero));
    }

    v_cleanup();
#endif
```

### 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
- [ ] 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

modules/core/src/split.simd.hpp

@@ -15,12 +15,12 @@ void split64s(const int64* src, int64** dst, int len, int cn);
 
 #ifndef CV_CPU_OPTIMIZATION_DECLARATIONS_ONLY
 
-#if CV_SIMD
+#if (CV_SIMD || CV_SIMD_SCALABLE)
 // see the comments for vecmerge_ in merge.cpp
 template<typename T, typename VecT> static void
 vecsplit_( const T* src, T** dst, int len, int cn )
 {
-    const int VECSZ = VecT::nlanes;
+    const int VECSZ = VTraits<VecT>::vlanes();
     int i, i0 = 0;
     T* dst0 = dst[0];
     T* dst1 = dst[1];
@@ -177,8 +177,8 @@ split_( const T* src, T** dst, int len, int cn )
 void split8u(const uchar* src, uchar** dst, int len, int cn )
 {
     CV_INSTRUMENT_REGION();
-#if CV_SIMD
-    if( len >= v_uint8::nlanes && 2 <= cn && cn <= 4 )
+#if (CV_SIMD || CV_SIMD_SCALABLE)
+    if( len >= VTraits<v_uint8>::vlanes() && 2 <= cn && cn <= 4 )
         vecsplit_<uchar, v_uint8>(src, dst, len, cn);
     else
 #endif
@@ -188,8 +188,8 @@ void split8u(const uchar* src, uchar** dst, int len, int cn )
 void split16u(const ushort* src, ushort** dst, int len, int cn )
 {
     CV_INSTRUMENT_REGION();
-#if CV_SIMD
-    if( len >= v_uint16::nlanes && 2 <= cn && cn <= 4 )
+#if (CV_SIMD || CV_SIMD_SCALABLE)
+    if( len >= VTraits<v_uint16>::vlanes() && 2 <= cn && cn <= 4 )
         vecsplit_<ushort, v_uint16>(src, dst, len, cn);
     else
 #endif
@@ -199,8 +199,8 @@ void split16u(const ushort* src, ushort** dst, int len, int cn )
 void split32s(const int* src, int** dst, int len, int cn )
 {
     CV_INSTRUMENT_REGION();
-#if CV_SIMD
-    if( len >= v_uint32::nlanes && 2 <= cn && cn <= 4 )
+#if (CV_SIMD || CV_SIMD_SCALABLE)
+    if( len >= VTraits<v_uint32>::vlanes() && 2 <= cn && cn <= 4 )
         vecsplit_<int, v_int32>(src, dst, len, cn);
     else
 #endif
@@ -210,8 +210,8 @@ void split32s(const int* src, int** dst, int len, int cn )
 void split64s(const int64* src, int64** dst, int len, int cn )
 {
     CV_INSTRUMENT_REGION();
-#if CV_SIMD
-    if( len >= v_int64::nlanes && 2 <= cn && cn <= 4 )
+#if (CV_SIMD || CV_SIMD_SCALABLE)
+    if( len >= VTraits<v_int64>::vlanes() && 2 <= cn && cn <= 4 )
         vecsplit_<int64, v_int64>(src, dst, len, cn);
     else
 #endif