[runtime] Implement encodeURI as single runtime function.

src/factory.h

Index: src/factory.h
diff --git a/src/factory.h b/src/factory.h
index 81252ebe13abcc9f44f78198417b994dd07a822f..51ba09dd2629db736967b47cc503fbb3eb2e67fa 100644
--- a/src/factory.h
+++ b/src/factory.h
@@ -560,6 +560,11 @@ class Factory final {
     return NewRangeError(MessageTemplate::kInvalidStringLength);
   }
 
+  Handle<Object> NewURIError() {
+    return NewError(isolate()->uri_error_function(),
+                    MessageTemplate::kURIMalformed);
+  }
+
   Handle<Object> NewError(Handle<JSFunction> constructor,
                           MessageTemplate::Template template_index,
                           Handle<Object> arg0 = Handle<Object>(),