Coroutine context is not cleared properly

[rocketraman]

The coroutine context is not cleared properly. This test fails:

  @Test
  fun `Context is restored after a context block is complete`() = runBlocking {
    assertTrue(ContextMap.empty)
    assertTrue(ContextStack.empty)
    withContext(CoroutineThreadContext(ThreadContextData(mapOf("myKey" to "myValue"), listOf("test")))) {
      assertEquals("myValue", ContextMap["myKey"])
      assertEquals("test", ContextStack.peek())
    }
    assertTrue(ContextMap.empty)
    assertTrue(ContextStack.empty)
  }