IssueTracker

Artifact used : androidx.appcompat:appcompat

Version used : 1.1.0

Theme used : Theme.AppCompat.Light.NoActionBar

Devices/Android versions reproduced on:

android 4.4.4
```xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

    <RadioGroup android:layout_width="match_parent" android:layout_height="match_parent">
        <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Hello World!"
                android:button="@null"
                app:layout_constraintBottom_toBottomOf="parent"
                app:layout_constraintLeft_toLeftOf="parent"
                app:layout_constraintRight_toRightOf="parent"
                app:layout_constraintTop_toTopOf="parent"/>
    </RadioGroup>


</androidx.constraintlayout.widget.ConstraintLayout>
```

android:button="@null" is not work at androidx.appcompat:appcompat:1.1.0

but it is work at androidx.appcompat:appcompat:1.0.2