a little improve of weak extensions and add tests for weak scopes

coroutines/src/commonTest/kotlin/WeakJobTests.kt

@@ -0,0 +1,36 @@
+import dev.inmo.micro_utils.coroutines.asyncWeak
+import dev.inmo.micro_utils.coroutines.launchWeak
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertTrue
+
+class WeakJobTests {
+    @Test
+    fun testWeakJob() = runTest {
+        var commonJobDone = false
+        var weakJobStarted = false
+        try {
+            coroutineScope {
+                launch {
+                    delay(1000)
+                    commonJobDone = true
+                }
+                asyncWeak {
+                    weakJobStarted = true
+                    delay(100500L)
+                    error("This must never happen")
+                }
+            }.await()
+        } catch (error: Throwable) {
+            assertTrue(error is CancellationException)
+            assertTrue(commonJobDone)
+            assertTrue(weakJobStarted)
+            return@runTest
+        }
+        error("Cancellation exception has not been thrown")
+    }
+}