[modules] Improve error messages.

test/mjsunit/modules-fail-star-exports-conflict.js

Index: test/mjsunit/modules-fail-star-exports-conflict.js
diff --git a/test/mjsunit/modules-fail-star-exports-conflict.js b/test/mjsunit/modules-fail-star-exports-conflict.js
deleted file mode 100644
index 6e2b2193422e770ee4f92f2a8dc0affa3f2d62dc..0000000000000000000000000000000000000000
--- a/test/mjsunit/modules-fail-star-exports-conflict.js
+++ /dev/null
@@ -1,10 +0,0 @@
-// Copyright 2016 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// MODULE
-
-export * from "modules-skip-star-exports-conflict.js";
-export * from "modules-skip-6.js";
-
-import {a} from "modules-fail-star-exports-conflict.js";