[wasm] Set up Table and Memory constructors

test/mjsunit/wasm/unicode-validation.js

Index: test/mjsunit/wasm/unicode-validation.js
diff --git a/test/mjsunit/wasm/unicode-validation.js b/test/mjsunit/wasm/unicode-validation.js
index b2e46030877ccd1223de013cafe83d73a1d7babb..ceaed0364fbee8fa690c5726d8b93bd59742660e 100644
--- a/test/mjsunit/wasm/unicode-validation.js
+++ b/test/mjsunit/wasm/unicode-validation.js
@@ -79,6 +79,7 @@ function checkImportsAndExports(imported_module_name, imported_function_name,
   } catch (err) {
     if (!shouldThrow) print(err);
     assertTrue(shouldThrow, "Should not throw error on valid names");
+    assertTrue(err instanceof Error, "exception should be an Error");
     assertContains("UTF-8", err.toString());
   }
   assertEquals(shouldThrow, hasThrown,