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

generators/src/org/jetbrains/kotlin/generators/tests/GenerateTests.kt

@@ -1129,6 +1129,10 @@ fun main(args: Array<String>) {
         testClass<AbstractCastTest>() {
             model("expression/cast/cases")
         }
+
+        testClass<AbstractLightReflectionTest>() {
+            model("reflection/light/cases")
+        }
     }
 
     testGroup("js/js.tests/test", "compiler/testData") {