Rename Mat::clone binding because it is used in Emscripten.

This is in emscripten 3.1.71 and above, cf
emscripten-core/emscripten#22734
There was a temptative fix upstream to no avail:
emscripten-core/emscripten#23132

Author: vrabaud

modules/js/src/core_bindings.cpp

@@ -520,7 +520,7 @@ EMSCRIPTEN_BINDINGS(binding_utils)
         .function("colRange", select_overload<Mat(int, int)const>(&cv::Mat::colRange))
         .function("colRange", select_overload<Mat(const Range&)const>(&cv::Mat::colRange))
         .function("step1", select_overload<size_t(int)const>(&cv::Mat::step1))
-        .function("clone", select_overload<Mat()const>(&cv::Mat::clone))
+        .function("mat_clone", select_overload<Mat()const>(&cv::Mat::clone))
         .function("depth", select_overload<int()const>(&cv::Mat::depth))
         .function("col", select_overload<Mat(int)const>(&cv::Mat::col))
         .function("dot", select_overload<double(const Mat&, const Mat&)>(&binding_utils::matDot))