[wasm] Inspect right control frames for unreachable flag

test/mjsunit/wasm/function-names.js

 // 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.
 
 // Flags: --expose-wasm
 
 load("test/mjsunit/wasm/wasm-constants.js");
 load("test/mjsunit/wasm/wasm-module-builder.js");
 
 var builder = new WasmModuleBuilder();
 
 var last_func_index = builder.addFunction("exec_unreachable", kSig_v_v)
-  .addBody([kExprUnreachable])
+  .addBody([kExprUnreachable]).index
 
 var illegal_func_name = [0xff];
 var func_names = [ "☠", illegal_func_name, "some math: (½)² = ¼", "" ];
 var expected_names = ["exec_unreachable", "☠", null,
                       "some math: (½)² = ¼", "", "main"];
 
 for (var func_name of func_names) {
   last_func_index = builder.addFunction(func_name, kSig_v_v)
     .addBody([kExprCallFunction, last_func_index]).index;
 }
@@ skipping 36 matching lines @@
   try {
     module.exports.main();
     assertFalse("should throw");
   } catch (e) {
     assertEquals(names.length, e.stack.length);
     for (var i = 0; i < names.length; ++i) {
       assertEquals(names[i], e.stack[i].getFunctionName());
     }
   }
 })();