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

tests/jerry/fail/module-014.js

@@ -15,5 +15,5 @@
 
 /* Import/export statements must be in the global scope. */
 if (true) {
-  import { c } from "tests/jerry/es2015/module-export-01.js";
+  import { c } from "../es2015/module-export-01.js";
 }