[Mirroring] MX VScrollBar flips up/down arrow skins when setting direction+layoutDirection styles to rtl

Found in 4.1.0.14456

Steps to reproduce:
1. Compile and run attached MXML file.
2. Note the position and direction of the ScrollBar icons and the embedded BitmapImage asset.
3. Click the "rtl" button to change direction+layoutDirection.
4. Note the position and direction of the ScrollBar icons and the embedded BitmapImage asset.

Actual Results:
VScrollBar arrow icon flips horizontally

Expected Results:
dont.

Workaround (if any):
n/a