JS backend: add the ability to get JS constructor function by class name and from instance. Support it for reified type parameters too. Add ability to get name of class.

#KT-5987 Fixed
 #KT-4115 Fixed

js/js.translator/testData/reflection/light/cases/jsClassName.kt

@@ -0,0 +1,26 @@
+package foo
+
+fun testWithInstance() {
+    assertEquals("A", A().jsClass.name)
+    assertEquals("B", B().jsClass.name)
+    assertEquals("O", O.jsClass.name)
+    assertEquals("E", E.X.jsClass.name)
+    assertEquals("Y", E.Y.jsClass.name)
+// TODO uncomment after KT-13338 is fixed
+//    assertEquals("E", E.Z.jsClass.name)
+}
+
+fun testWithClassReference() {
+    assertEquals("A", jsClass<A>().name)
+    assertEquals("B", jsClass<B>().name)
+    assertEquals("O", jsClass<O>().name)
+    assertEquals("I", jsClass<I>().name)
+    assertEquals("E", jsClass<E>().name)
+}
+
+fun box(): String {
+    testWithInstance()
+    testWithClassReference()
+
+    return "OK"
+}