Fix issue with RTL locales and zoomScale

Summary:
Changelog:
[iOS][Fixed] - When in an RTL locale on iOS, e.nativeEvent.zoomScale is -1. This seems to cause erratic blank spaces that don't recover as you scroll. Set the value to 1 instead when negative.

Differential Revision: D36499121

fbshipit-source-id: f82812ca00ae4162fbff617df8c716a4964b3a8f

Libraries/Lists/VirtualizedList.js

@@ -1627,8 +1627,8 @@ class VirtualizedList extends React.PureComponent<Props, State> {
       this._hasWarned.perf = true;
     }
 
-    const zoomScale = e.nativeEvent.zoomScale;
-
+    // For invalid negative values (w/ RTL), set this to 1.
+    const zoomScale = e.nativeEvent.zoomScale < 0 ? 1 : e.nativeEvent.zoomScale;
     this._scrollMetrics = {
       contentLength,
       dt,