Add tests for Channel closed with an exception

[murfel]

No description provided.

[dkhalanskyjb]

This syntax means the comment is a KDoc and refers to the entity directly below it. To make this a normal multiline comment for separating groups of tests, use /*.

That said, I think the separation is easy to break accidentally. Why not introduce separate classes to make this more robust?

class ClosedChannelTest: TestBase() {
    /**
     * Properties.
     *
     * Properties stay the same regardless of whether the channel was closed with or without exception.
     */
    class PropertiesTests: TestBase() {
        
    }
}

[dkhalanskyjb]

Proposal:

    fun TestChannelKind.Companion.runTestForEach(
        testBody: suspend CoroutineScope.(TestChannelKind) -> Unit
    ): TestResult = runTest {
        TestChannelKind.entries.forEach { kind ->
            testBody(kind)
        }
    }

May be more convenient, with how often this pattern occurs.