Added assertios to remap and warpAffine functions

Remap and warpAffine functions do not support more than 4 channels in
Bicubic and Lanczos4 interpolation modes. Assertions were added.
resolve #8272

modules/imgproc/src/imgwarp.cpp

@@ -5019,10 +5019,14 @@ void cv::remap( InputArray _src, OutputArray _dst,
     {
         if( interpolation == INTER_LINEAR )
             ifunc = linear_tab[depth];
-        else if( interpolation == INTER_CUBIC )
+        else if( interpolation == INTER_CUBIC ){
             ifunc = cubic_tab[depth];
-        else if( interpolation == INTER_LANCZOS4 )
+            CV_Assert( _src.channels() <= 4 );
+        }
+        else if( interpolation == INTER_LANCZOS4 ){
             ifunc = lanczos4_tab[depth];
+            CV_Assert( _src.channels() <= 4 );
+        }
         else
             CV_Error( CV_StsBadArg, "Unknown interpolation method" );
         CV_Assert( ifunc != 0 );
@@ -5962,6 +5966,10 @@ void cv::warpAffine( InputArray _src, OutputArray _dst,
 {
     CV_INSTRUMENT_REGION()
 
+    int interpolation = flags & INTER_MAX;
+    CV_Assert( _src.channels() <= 4 || (interpolation != INTER_LANCZOS4 &&
+                                        interpolation != INTER_CUBIC) );
+
     CV_OCL_RUN(_src.dims() <= 2 && _dst.isUMat() &&
                _src.cols() <= SHRT_MAX && _src.rows() <= SHRT_MAX,
                ocl_warpTransform_cols4(_src, _dst, _M0, dsize, flags, borderType,
@@ -5980,7 +5988,6 @@ void cv::warpAffine( InputArray _src, OutputArray _dst,
 
     double M[6];
     Mat matM(2, 3, CV_64F, M);
-    int interpolation = flags & INTER_MAX;
     if( interpolation == INTER_AREA )
         interpolation = INTER_LINEAR;