[guava] JobListenableFuture.isCancelled() throws if future is completed exceptionally

[vadimsemenov]

The bug was introduced in #2222

    @Test
    fun testFailedFuture_isCancelledDoesNotThrow() = runTest {
        val future = future(context = NonCancellable) {
            throw TestException()
        }
        yield()
        assertTrue(future.isDone)
        assertFalse(future.isCancelled)  // throws ExecutionException here.
        val thrown = assertFailsWith<ExecutionException> { future.get() }
        assertTrue(thrown.cause is TestException)
    }

Uninteraptables.getUninterruptibly(future) throws ExecutionException if the future is completed exceptionally.