Tests are failing on iOS 12.2

https://travis-ci.org/apache/cordova-plugin-inappbrowser/jobs/547251173

```
cordova-paramedic: Tests failed to complete; ending appium session. The error is:
Error: [context("WEBVIEW_5181.2")] Error response status: 13, UnknownError - An unknown server-side error occurred while processing the command. Selenium error: An unknown server-side error occurred while processing the command. Original error: Remote debugger error with code '-32601': 'Page' domain was not found
at exports.newError (/Users/travis/.nvm/versions/node/v6.17.1/lib/node_modules/cordova-paramedic/node_modules/wd/lib/utils.js:152:13)
at /Users/travis/.nvm/versions/node/v6.17.1/lib/node_modules/cordova-paramedic/node_modules/wd/lib/callbacks.js:36:19
at /Users/travis/.nvm/versions/node/v6.17.1/lib/node_modules/cordova-paramedic/node_modules/wd/lib/webdriver.js:194:5
at Request._callback (/Users/travis/.nvm/versions/node/v6.17.1/lib/node_modules/cordova-paramedic/node_modules/wd/lib/http-utils.js:89:7)
at Request.self.callback (/Users/travis/.nvm/versions/node/v6.17.1/lib/node_modules/cordova-paramedic/node_modules/request/request.js:185:22)
at emitTwo (events.js:106:13)
at Request.emit (events.js:191:7)
at Request. (/Users/travis/.nvm/versions/node/v6.17.1/lib/node_modules/cordova-paramedic/node_modules/request/request.js:1161:10)
at emitOne (events.js:96:13)
at Request.emit (events.js:188:7)
From previous event:
at ParamedicSauceLabs.runSauceTests (/Users/travis/.nvm/versions/node/v6.17.1/lib/node_modules/cordova-paramedic/lib/ParamedicSauceLabs.js:459:14)
at ParamedicRunner.runTests (/Users/travis/.nvm/versions/node/v6.17.1/lib/node_modules/cordova-paramedic/lib/paramedic.js:337:58)
at Q.then.then.then (/Users/travis/.nvm/versions/node/v6.17.1/lib/node_modules/cordova-paramedic/lib/paramedic.js:89:29)
```

https://app.saucelabs.com/tests/b3c7f179af914ced899a8daa222da1d0 shows this happening quite early:


Start with the linked Travis CI job 547251173 and the Sauce Labs run to confirm where the iOS 12.2 test fails. Trace the Appium remote-debugger error and compare the failing WebView context with a supported iOS version; done means the Cordova plugin tests complete successfully on iOS 12.2.

Written by the indexing model from the issue text.