add test

Author: eagleoflqj

test/other/test_em_js_main.out

@@ -2,3 +2,4 @@ in main
 hello from side module 42 + hello
 hello again
 hello from void func
+indirect ptr value: 0

test/other/test_em_js_side.c

@@ -14,9 +14,14 @@ EM_JS(void, js_side_func_void, (), {
   out(`hello from void func`);
 });
 
+EM_JS(void, js_side_func_indirect_ptr, (char **pptr), {
+  out(`indirect ptr value: ${pptr}`);
+});
+
 int test_side() {
   js_side_func(42, "hello");
   js_side_func2("hello again");
   js_side_func_void();
+  js_side_func_indirect_ptr(NULL);
   return 0;
 }