esm: Fix use-after-free on error during module evaluation

E.g. if during evaluation of module A, we start loading module B and
an error occurs. This results in a call to js_free_modules() with
JS_FREE_MODULE_NOT_EVALUATED, and since module A isn't yet evaluated,
it gets freed prematurely.

To solve this we improve js_free_modules() to ensure `eval_mark` is not
set. Once js_evaluate_module() returns for module A, it will notice that
an exception occurred and call js_free_modules() with
JS_FREE_MODULE_NOT_EVALUATED. Since `eval_mark` has been cleared by then,
module A gets cleaned up as well.

quickjs.c

@@ -2286,7 +2286,8 @@ static void js_free_modules(JSContext *ctx, JSFreeModuleEnum flag)
         JSModuleDef *m = list_entry(el, JSModuleDef, link);
         if (flag == JS_FREE_MODULE_ALL ||
             (flag == JS_FREE_MODULE_NOT_RESOLVED && !m->resolved) ||
-            (flag == JS_FREE_MODULE_NOT_EVALUATED && !m->evaluated)) {
+            (flag == JS_FREE_MODULE_NOT_EVALUATED && !m->evaluated
+                && !m->eval_mark)) {
             js_free_module_def(ctx, m);
         }
     }