Remove wrapper around ListEmptyComponent (facebook#24339)

Summary:
This pull request fixes facebook#24257.

The wrapper around ListEmptyComponent doesn't allow to use flex on the ListEmptyComponent.
The wrapper was removed in this [commit](facebook@db061ea), and then put back in this [commit](facebook@e94d344) but I think the relevant part was removing the condition on `itemCount !== 0` to apply the inversionStyle on the ScrollView and everything is still working without the wrapper.

[GENERAL] [FIXED] - Remove wrapper around ListEmptyComponent
Pull Request resolved: facebook#24339

Differential Revision: D14822221

Pulled By: cpojer

fbshipit-source-id: 623e1ab3f228e9b75b92cdcd568683232a403c1a

Author: AntoineDoubovetzky

Libraries/Lists/VirtualizedList.js

@@ -873,17 +873,19 @@ class VirtualizedList extends React.PureComponent<Props, State> {
         <ListEmptyComponent />
       )): any);
       cells.push(
-        <View key="$empty" style={inversionStyle}>
-          {React.cloneElement(element, {
-            onLayout: event => {
-              this._onLayoutEmpty(event);
-              if (element.props.onLayout) {
-                element.props.onLayout(event);
-              }
-            },
-            style: element.props.style,
-          })}
-        </View>,
+        React.cloneElement(element, {
+          key: '$empty',
+          onLayout: event => {
+            this._onLayoutEmpty(event);
+            if (element.props.onLayout) {
+              element.props.onLayout(event);
+            }
+          },
+          style: StyleSheet.compose(
+            inversionStyle,
+            element.props.style,
+          ),
+        }),
       );
     }
     if (ListFooterComponent) {

Libraries/Lists/__tests__/__snapshots__/VirtualizedList-test.js.snap

@@ -668,11 +668,7 @@ exports[`VirtualizedList renders empty list with empty component 1`] = `
     >
       <header />
     </View>
-    <View
-      style={null}
-    >
-      <empty />
-    </View>
+    <empty />
     <View
       onLayout={[Function]}
     >