Fix tree-shaking named import on wrapped module (#1683)

src/scope-hoisting/hoist.js

@@ -110,6 +110,7 @@ module.exports = {
           ])
         );
 
+        asset.cacheData.exports = {};
         asset.cacheData.isCommonJS = true;
         asset.cacheData.isES6Module = false;
       } else {

test/integration/scope-hoisting/es6/import-wrapped/a.js

@@ -0,0 +1,3 @@
+import {foo} from './b'
+
+output = foo

test/integration/scope-hoisting/es6/import-wrapped/b.js

@@ -0,0 +1 @@
+export const foo = eval("'bar'")

test/scope-hoisting.js

@@ -311,6 +311,15 @@ describe('scope hoisting', function() {
       let output = await run(b);
       assert.deepEqual(output, 'foo');
     });
+
+    it('should support named imports on wrapped modules', async function() {
+      let b = await bundle(
+        __dirname + '/integration/scope-hoisting/es6/import-wrapped/a.js'
+      );
+
+      let output = await run(b);
+      assert.deepEqual(output, 'bar');
+    });
   });
 
   describe('commonjs', function() {