Merge pull request #27510 from fengyuentau:4x/core/reduce_simd

core: vectorize cv::reduce #27510

- [ ] ~reduceR_~ Dropped due to performance
- [x] reduceC_

### Pull Request Readiness Checklist

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

- [x] I agree to contribute to the project under Apache 2 License.
- [x] 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
- [x] 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/test/test_mat.cpp

@@ -170,7 +170,7 @@ int Core_ReduceTest::checkOp( const Mat& src, int dstType, int opType, const Mat
         getMatTypeStr( dstType, dstTypeStr );
         const char* dimStr = dim == 0 ? "ROWS" : "COLS";
 
-        snprintf( msg, sizeof(msg), "bad accuracy with srcType = %s, dstType = %s, opType = %s, dim = %s",
+        snprintf( msg, sizeof(msg), "bad accuracy with srcType = %s, dstType = %s, opType = %s, dim = %s\n",
                 srcTypeStr.c_str(), dstTypeStr.c_str(), opTypeStr, dimStr );
         ts->printf( cvtest::TS::LOG, msg );
         return cvtest::TS::FAIL_BAD_ACCURACY;