[K/JS] Add the ability to turn off polyfills generating

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JSCompilerArguments.kt

@@ -267,6 +267,12 @@ class K2JSCompilerArguments : CommonCompilerArguments() {
     )
     var generateDts: Boolean by FreezableVar(false)
 
+    @Argument(
+        value = "-Xgenerate-polyfills",
+        description = "Generate polyfills for features from the ES6+ standards."
+    )
+    var generatePolyfills: Boolean by FreezableVar(true)
+
     @Argument(
         value = "-Xstrict-implicit-export-types",
         description = "Generate strict types for implicitly exported entities inside d.ts files. Available in IR backend only."