[Bug] Class cast error in for xctestrun Xctestrun.kt without SkipTestIdentifiers

[BorisOsipov]

Issue:

Marathon exited with exception

E 14:18:52.899 [main @coroutine#1] <com.malinskiy.marathon.Marathon> null cannot be cast to non-null type kotlin.Array<kotlin.Any>

I've added stacktrace to log

E 14:18:52.899 [main @coroutine#1] <com.malinskiy.marathon.Marathon> com.malinskiy.marathon.ios.xctestrun.Xctestrun.<init>(Xctestrun.kt:61)
com.malinskiy.marathon.ios.xctestrun.Xctestrun.<init>(Xctestrun.kt:17)
com.malinskiy.marathon.ios.IOSTestParser.extract(IOSTestParser.kt:30)
com.malinskiy.marathon.Marathon.runAsync(Marathon.kt:87)
com.malinskiy.marathon.Marathon$runAsync$1.invokeSuspend(Marathon.kt)
kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
kotlinx.coroutines.DispatchedTask.run(Dispatched.kt:241)
kotlinx.coroutines.EventLoopImplBase.processNextEvent(EventLoop.common.kt:270)
kotlinx.coroutines.BlockingCoroutine.joinBlocking(Builders.kt:79)
kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking(Builders.kt:54)
kotlinx.coroutines.BuildersKt.runBlocking(Unknown Source)
kotlinx.coroutines.BuildersKt__BuildersKt.runBlocking$default(Builders.kt:36)
kotlinx.coroutines.BuildersKt.runBlocking$default(Unknown Source)
com.malinskiy.marathon.Marathon.run(Marathon.kt:62)
com.malinskiy.marathon.cli.ApplicationViewKt$main$1.invoke(ApplicationView.kt:47)
com.malinskiy.marathon.cli.ApplicationViewKt$main$1.invoke(ApplicationView.kt)
com.xenomachina.argparser.SystemExitExceptionKt.mainBody(SystemExitException.kt:74)
com.xenomachina.argparser.SystemExitExceptionKt.mainBody$default(SystemExitException.kt:72)
com.malinskiy.marathon.cli.ApplicationViewKt.main(ApplicationView.kt:26)

I did debug and found root cause - in my .xctestrun file there is no SkipTestIdentifiers and com.malinskiy.marathon.ios.xctestrun.Xctestrun#skipTestIdentifiers cause crash.

versions: Xcode 11.2.1 Marathon 0.5.1 develop#88d292d158a9b6