Back out "Change ImageBackground to work with percentage image sizes"

Summary:
Original commit changeset: cec3802d30b7

See my comment on original diff: D9307123

The diff regresses ImageBackground in some cases, so I'm reverting until we can re-work the diff to handle existing usages in an expected way.

Differential Revision: D9790698

fbshipit-source-id: 23ad670e004980f22bd1413eca3692f51beff717

Libraries/Image/ImageBackground.js

@@ -76,8 +76,8 @@ class ImageBackground extends React.Component<$FlowFixMeProps> {
               // So, we have to proxy/reapply these styles explicitly for actual <Image> component.
               // This workaround should be removed after implementing proper support of
               // intrinsic content size of the <Image>.
-              width: '100%',
-              height: '100%',
+              width: style.width,
+              height: style.height,
             },
             imageStyle,
           ]}