[AC-6017] Crash on Nightly Version when Using WebView [iOS only]

   - (NSString *)evalJS:(id)code
   {
     ENSURE_SINGLE_ARG(code, NSString);
     /*
        Using GCD either through dispatch_async/dispatch_sync or TiThreadPerformOnMainThread
        does not work reliably for evalJS on 5.0 and above. See sample in TIMOB-7616 for fail case.
        */
     if (![NSThread isMainThread]) {
       inKJSThread = YES;
       [self performSelectorOnMainThread:@selector(evalJS:) withObject:code waitUntilDone:YES];
       inKJSThread = NO;
     } else {
       evalResult = [[(TiUIWebView *)[self view] stringByEvaluatingJavaScriptFromString:code] retain];
     }
     return (inKJSThread ? evalResult : [evalResult autorelease]);
   }
   

   - (NSString *)evalJS:(id)args
   {
     KrollCallback *callback = nil;
     NSString *code = nil;
     ENSURE_ARG_AT_INDEX(code, args, 0, NSString); // Conform to class because that's good practice
     if ([args count] > 1) {
       ENSURE_ARG_AT_INDEX(callback, args, 1, KrollCallback);
     }
   
     // Handle async
     if (callback != nil) {
   
       // Spin off a thread that will invoke on main thread and fire callback, then return nil immediately
       dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
         dispatch_async(dispatch_get_main_queue(), ^{
           NSString *result = [(TiUIWebView *)[self view] stringByEvaluatingJavaScriptFromString:code];
           [callback call:@[ result ] thisObject:nil];
         });
       });
       return nil;
     }
   
     /*
        Using GCD either through dispatch_async/dispatch_sync or TiThreadPerformOnMainThread
        does not work reliably for evalJS on 5.0 and above. See sample in TIMOB-7616 for fail case.
        */
     if (![NSThread isMainThread]) {
       inKJSThread = YES;
       [self performSelectorOnMainThread:@selector(evalJS:) withObject:code waitUntilDone:YES];
       inKJSThread = NO;
     } else {
       evalResult = [[(TiUIWebView *)[self view] stringByEvaluatingJavaScriptFromString:code] retain];
     }
     return (inKJSThread ? evalResult : [evalResult autorelease]);
   }