JS: support @Before and @After annotations in kotlin.test

libraries/kotlin.test/js/it/src/test/kotlin/MainTest.kt

@@ -1,13 +1,24 @@
 import kotlin.test.*
 
+
+var value = 5
+
 class SimpleTest {
 
+    @Before fun beforeFun() {
+        value *= 2
+    }
+
+    @After fun afterFun() {
+        value /= 2
+    }
+
     @Test fun testFoo() {
-        assertEquals(20, foo())
+        assertNotEquals(value, foo())
     }
 
     @Test fun testBar() {
-        assertEquals(10, foo())
+        assertEquals(value, foo())
     }
 
     @Ignore @Test fun testFooWrong() {

libraries/kotlin.test/js/src/main/kotlin/kotlin/test/Annotations.kt

@@ -24,4 +24,14 @@ public annotation class Test
 /**
  * Marks a test or a suite as ignored/pending.
  */
-public annotation class Ignore
+public annotation class Ignore
+
+/**
+ * Marks a function to be invoked before each test.
+ */
+public annotation class Before
+
+/**
+ * Marks a function to be invoked after each test.
+ */
+public annotation class After