JS backend: report diagnostic for class literal(Foo::class) instead of crash with Exception.

compiler/testData/cli/js/diagnosticForClassLiteral.args

@@ -0,0 +1,4 @@
+$TESTDATA_DIR$/diagnosticForClassLiteral.kt
+-no-stdlib
+-output
+$TEMP_DIR$/out.js

compiler/testData/cli/js/diagnosticForClassLiteral.kt

@@ -0,0 +1,7 @@
+package foo
+
+class A
+
+fun test() {
+    A::class
+}

compiler/testData/cli/js/diagnosticForClassLiteral.out

@@ -0,0 +1,3 @@
+WARNING: compiler/testData/cli/js/diagnosticForClassLiteral.kt: (6, 5) The expression is unused
+ERROR: compiler/testData/cli/js/diagnosticForClassLiteral.kt: (6, 6) Reflection types can't be loaded. Please ensure that you have Kotlin Runtime in your classpath
+COMPILATION_ERROR

compiler/tests/org/jetbrains/kotlin/cli/KotlincExecutableTestGenerated.java

@@ -183,6 +183,12 @@ public class KotlincExecutableTestGenerated extends AbstractKotlincExecutableTes
             JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/cli/js"), Pattern.compile("^(.+)\\.args$"), false);
         }
 
+        @TestMetadata("diagnosticForClassLiteral.args")
+        public void testDiagnosticForClassLiteral() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/cli/js/diagnosticForClassLiteral.args");
+            doJsTest(fileName);
+        }
+
         @TestMetadata("diagnosticForUnhandledElements.args")
         public void testDiagnosticForUnhandledElements() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/cli/js/diagnosticForUnhandledElements.args");

js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/ExpressionVisitor.java

@@ -183,11 +183,6 @@ public final class ExpressionVisitor extends TranslatorVisitor<JsNode> {
         return newVar(name, initializer).source(expression);
     }
 
-    @Override
-    public JsNode visitClassLiteralExpression(@NotNull JetClassLiteralExpression expression, @NotNull TranslationContext context) {
-        throw new UnsupportedOperationException("Class literals are not yet supported: " + expression.getText());
-    }
-
     @Override
     @NotNull
     public JsNode visitCallableReferenceExpression(@NotNull JetCallableReferenceExpression expression, @NotNull TranslationContext context) {