Resolve module paths relative to the current module (#2976)

The current module implementation resolves module paths relative to the
current working directory, but paths should be resolved relative to the
currently evaluated module/source.

This requires a change in the jerry_port_normalize_path port API
function, so that it also takes the current module path as an argument.
On the engine side, we now also create a module object for the main
script, so that we can properly identify the base path for other
modules.

Co-authored-by: Marko Fabo <mfabo@inf.u-szeged.hu>
JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu

jerry-main/main-unix.c

@@ -151,7 +151,7 @@ print_unhandled_exception (jerry_value_t error_value) /**< error value */
   }
   else
   {
-    jerry_size_t string_end = jerry_string_to_char_buffer (err_str_val, err_str_buf, err_str_size);
+    jerry_size_t string_end = jerry_string_to_utf8_char_buffer (err_str_val, err_str_buf, err_str_size);
     assert (string_end == err_str_size);
     err_str_buf[string_end] = 0;