Remove emscripten test

emscripten/a.cpp

-#include <string>
-#include <fstream>
-#include <streambuf>
-#include <iostream>
-
-#define private public
-#include "rapidjson/document.h"
-
-int main() {
-    // std::ifstream in_file("config.json", std::ios::in);
-    rapidjson::Document json_config_;
-    // std::string json_string(
-    //         (std::istreambuf_iterator<char>(in_file)),
-    //         std::istreambuf_iterator<char>());
-    std::string json_string("{\"float_test\": 75.0}");
-    // if (!json_string.empty()) {
-        json_config_.Parse(json_string.c_str());
-    // }
-
-    printf("%p\n", &json_config_);
-    printf("%p\n", &json_config_.data_.o.members[0].value.data_.n.d);
-
-    std::cout << json_config_["float_test"].GetDouble() << std::endl;
-}
\ No newline at end of file