Links with target _blank are not working on iOS inside inAppBrowser when wkwebview is enabled

Links with target _blank are not working on iOS when they are opened from the inAppBrowser and wkwebview is enabled. This is also an issue with a form element which has target _blank. Nothing happens when you tap link or submit form. Links without _blank are working correctly.

Tested with the master version 3.1.0-dev and setting `usewkwebview=yes`

Happens on various iPhones and simulator.

Here is the repo for minimal reproduction of the issue:
https://github.com/teroauralinna/cordova-iab-wkwebview

In the issue demo, click **Open inAppBrowser** and then **Link with _blank doesn't work!** => nothing happens

Start by running the linked minimal reproduction with the master 3.1.0-dev version and `usewkwebview=yes`. Compare the inAppBrowser behavior for links and form elements with `target=_blank` against links without that target, and trace the plugin's iOS WKWebView handling. Done means both links and forms with `target=_blank` open as expected.

Written by the indexing model from the issue text.