Default example test crashes

Following the docs with the basic setup and sample test:

`class MyFirstEarlGreyTest: XCTestCase {

func testExample() {
let application: XCUIApplication = XCUIApplication()
application.launch()
EarlGrey.setHostApplicationCrashHandler(GREYHostApplicationCrashHandler?)
}
}`

crashes after opening and closing the app a couple of times with:

Host background port not assigned. Application under test may have failed to launch and/or does not link to EarlGrey's AppFramework.

What am I missing.. I linked the AppFramework

Start by reproducing the documented basic setup and sample test, then verify that the application under test links the EarlGrey AppFramework. The issue is resolved when repeated app launches no longer produce the host background port error.

Written by the indexing model from the issue text.