IssueTracker

Component used: ViewBinding with merge tag
Version used: Android Gradle Plugin 3.6.3
Devices/Android versions reproduced on: Android Studio 3.6.3 with AGP 3.6.3

If this is a bug in the library, we would appreciate if you could attach:
The XML is:

```
<?xml version="1.0" encoding="utf-8"?>
<merge
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:elevation="0dp">

        <slack.uikit.components.pageheader.SKToolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/transparent"
            app:navigationIcon="@drawable/sk_icon_close"/>

    </com.google.android.material.appbar.AppBarLayout>

    <androidx.core.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clipChildren="false"
        android:clipToPadding="false"
        android:overScrollMode="never"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

        <include
            layout="@layout/fullscreen_takeover_scrollable_content"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/>

    </androidx.core.widget.NestedScrollView>

    <include
        layout="@layout/fullscreen_takeover_sticky_content"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"/>

</merge>
```
And the error is:

```
/Users/sw/dev/slack-android/app/build/generated/data_binding_base_class_source_out/internalDebug/out/com/Slack/databinding/FullscreenTakeoverViewV2Binding.java:25: error: cannot find symbol
  public final merge mainContent;
               ^
  symbol:   class merge
  location: class FullscreenTakeoverViewV2Binding/Users/sw/dev/slack-android/app/build/generated/data_binding_base_class_source_out/internalDebug/out/com/Slack/databinding/FullscreenTakeoverViewV2Binding.java:31: error: cannot find symbol
      @NonNull merge mainContent, @NonNull SKToolbar toolbar) {
               ^
  symbol:   class merge
  location: class FullscreenTakeoverViewV2Binding
> Task :app:kaptInternalDebugKotlin FAILED
```
- Sample project to trigger the issue.
- A screenrecord or screenshots showing the issue (if UI related).