iOS wrong event.url in IAB events (beforeload, loadstart and loadstop)

# Bug Report

## Problem

I have ionic/cordova IOS/Android/Electron project that downloads zip, unzips it and shows html/css/js from that zip.
It worked OK while on UIWebView and cordova-plugin-inappbrowser v3.2.0, but migrating to WKWebView and latest inappbrowser (4.0 from github master branch) proved a bit harder than I expected.

After PR #693 and my PR #778 I managed to open local files using `file://` in v4 branch, but XHR did not work.
I decided to ditch local files opening with file:// and I implemented local httpd server (using my fork of [cordova-httpd](https://github.com/guycalledseven/cordova-httpd)), and managed to get XHR to work again BUT found different and very strange bug.

My app relies on using IAB `beforeload`, `loadstart` and `loadstop` events which handle detection if outbond links were pressed in local html files etc. When page opens, and event gets triggered I can check `event.url` and see on which url the event got triggered.

### What does actually happen?

While using latest version of `cordova-plugin-inappbrowser` url in `event.url` comes wrong.

Instead of `http://127.0.0.1:8888/20612/21018.html` I get `http://localhost:8080/127.0.0.1:8888/20612/21018.html`.

Notice the extra string: **`localhost:8080/`**.

## Information

Let's say that my local data is downloaded into
`/Users/{username}/Library/Developer/CoreSimulator/Devices/B0B80D63-64FD-4FBD-879B-92D2204BA713/data/Containers/Data/Application/1625CAAA-AF07-4706-BDA2-DB2D85938AB8/Documents/WebRoot`, and that is a web root of local webserver.

So the final file I am about to load is located locally in `/Users/{username}/Library/Developer/CoreSimulator/Devices/B0B80D63-64FD-4FBD-879B-92D2204BA713/data/Containers/Data/Application/1625CAAA-AF07-4706-BDA2-DB2D85938AB8/Documents/WebRoot/20612/21018.html`

Local web server is started on `http://127.0.0.1:8888/`

The url passed to IAB for opening is `http:/127.0.0.1:8888/20612/21018.html`

**This works ok**, page gets opened. However, when ANY event is triggered, the `event.url` returned is: `http://localhost:8080/127.0.0.1:8888/20612/21018.html`

I have 0 (zero) references to `localhost:8080` in my code or `config.xml`.
However, I have found out that after preparing project, this gets generated:

1. in `platforms/ios//config.xml`:

```


```

2. and in `platforms/ios/ios.json`:
```
...
{
"xml": "",
"count": 1
},
{
"xml": "",
"count": 1
},
...
```

All in all - `allow-navigation` configuration shouldn't have ANY impact on `event.url`.

### Command or Code

```
windowOptions : InAppBrowserOptions | string = {
location : 'no',
hidden : 'no',
zoom : 'yes',
useWideViewPort: 'yes',
hardwareback : 'yes',
hidenavigationbuttons : 'yes',
hideurlbar : 'yes',
mediaPlaybackRequiresUserAction : 'no',
shouldPauseOnSuspend : 'yes',
closebuttoncaption : this.translate.instant('book.close'),
disallowoverscroll : 'no',
toolbar : 'no',
toolbartranslucent : 'yes',
enableViewportScale : 'yes',
allowInlineMediaPlayback : 'yes',
presentationstyle : 'fullscreen',
fullscreen : 'yes',
footer: 'no',
beforeload: 'get'
};

var url = "http:/127.0.0.1:8888/20612/21018.html";
this.windowOptions = this.toOptionsString(this.windowOptions);
var browserIab = cordova.InAppBrowser.open(url, '_blank', this.windowOptions);

browserIab.addEventListener('beforeload', (event, load) => {
if (this.isUrlHomePage(event.url))
{
browserIab.close();
return;
}
});

private toOptionsString(optionsObject) {
return Object.keys(optionsObject).map((key) => key + '=' + optionsObject[key]).join(',');
}
```

### Environment, Platform, Device

iOS 13.7

### Version information

```
Ionic:

Ionic CLI : 6.11.8 (/usr/local/lib/node_modules/@ionic/cli)
Ionic Framework : ionic-angular 3.9.4
@ionic/app-scripts : 3.2.3

Cordova:

Cordova CLI : 10.0.0
Cordova Platforms : ios 5.1.1
Cordova Plugins : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview 2.5.3, cordova-plugin-ionic 5.4.7, (and 20 other plugins)

Utility:

cordova-res : 0.15.1
native-run : 1.0.0

System:

ios-sim : 8.0.2
NodeJS : v12.18.3 (/usr/local/Cellar/node@12/12.18.3/bin/node)
npm : 6.14.8
OS : macOS Catalina
Xcode : Xcode 11.7 Build version 11E801a
```

## Checklist

- [X] I searched for existing GitHub issues
- [ ] I updated all Cordova tooling to most recent version
- [X] I included all the necessary information above

Start at cordova.InAppBrowser.open and the beforeload, loadstart, and loadstop event paths described in the report. Compare event.url with the supplied local-server URL, using the generated platforms/ios//config.xml and platforms/ios/ios.json as configuration evidence. Reproduce on iOS 13.7 with the shown options; done means these events report the opened URL without the unexpected localhost:8080 prefix.

Written by the indexing model from the issue text.