[K/JS] Introduce v2015 target

js/js.frontend/src/org/jetbrains/kotlin/js/config/EcmaVersion.java

@@ -19,10 +19,10 @@ package org.jetbrains.kotlin.js.config;
 import org.jetbrains.annotations.NotNull;
 
 public enum EcmaVersion {
-    v3, v5;
+    es5, es2015;
 
     @NotNull
     public static EcmaVersion defaultVersion() {
-        return v5;
+        return es5;
     }
 }

js/js.tests/test/org/jetbrains/kotlin/js/testOld/utils/JsTestUtils.java

@@ -36,7 +36,7 @@ public final class JsTestUtils {
 
     @NotNull
     public static EnumSet<EcmaVersion> successOnEcmaV5() {
-        return EnumSet.of(EcmaVersion.v5);
+        return EnumSet.of(EcmaVersion.es5);
     }
 
     @NotNull