Generate equals/hashCode(): Use class literals when possible

#KT-18683 Fixed

idea/testData/codeInsight/generate/equalsWithHashCode/noVarsJS.kt.after

@@ -0,0 +1,16 @@
+// PLATFORM: JavaScript
+class A {
+    fun foo() {
+
+    }
+
+    <caret>override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other == null || other::class.js != this::class.js) return false
+        return true
+    }
+
+    override fun hashCode(): Int {
+        return this::class.js.hashCode()
+    }
+}