Assert that we don't mix K and J elements

pkg/compiler/lib/src/js_emitter/full_emitter/setup_program_builder.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart2js.js_emitter.full_emitter;
 
 // TODO(ahe): Share these with js_helper.dart.
 const FUNCTION_INDEX = 0;
 const NAME_INDEX = 1;
 const CALL_NAME_INDEX = 2;
@@ skipping 111 matching lines @@
     'classFieldsExtractor': classFieldsExtractorAccess,
     'instanceFromClassId': instanceFromClassIdAccess,
     'initializeEmptyInstance': initializeEmptyInstanceAccess,
     'allClasses': allClassesAccess,
     'debugFastObjects': DEBUG_FAST_OBJECTS,
     'isTreeShakingDisabled': backend.mirrorsData.isTreeShakingDisabled,
     'precompiled': precompiledAccess,
     'finishedClassesAccess': finishedClassesAccess,
     'needsMixinSupport': emitter.needsMixinSupport,
     'needsNativeSupport': program.needsNativeSupport,
-    'enabledJsInterop': backend.nativeBasicData.isJsInteropUsed,
+    'enabledJsInterop': closedWorld.nativeData.isJsInteropUsed,
     'jsInteropBoostrap': backend.jsInteropAnalysis.buildJsInteropBootstrap(),
     'isInterceptorClass':
         namer.operatorIs(closedWorld.commonElements.jsInterceptorClass),
     'isObject': namer.operatorIs(closedWorld.commonElements.objectClass),
     'specProperty': js.string(namer.nativeSpecProperty),
     'trivialNsmHandlers': emitter.buildTrivialNsmHandlers(),
     'hasRetainedMetadata': backend.mirrorsData.hasRetainedMetadata,
     'types': typesAccess,
     'objectClassName': js.quoteName(
         namer.runtimeTypeName(closedWorld.commonElements.objectClass)),
@@ skipping 705 matching lines @@
 (function() {
   var result = $array[$index];
   if ($check) {
     throw new Error(
         name + ": expected value of type \'$type\' at index " + ($index) +
         " but got " + (typeof result));
   }
   return result;
 })()''';
 }