SF: Reverse dumpsys layer order to top-to-bottom

The layer lists in `dumpsys SurfaceFlinger` were printed in bottom-to-top Z-order, which is inconsistent with other dumps like `dumpsys window`.

This CL reverses the iteration to display layers from top-to-bottom, making debugging more intuitive and consistent with other tools.

Bug: 393401895
Test: Manually ran 'adb shell dumpsys SurfaceFlinger' and verified the "Composition list" and "HWC layers" tables are now in top-to-bottom Z-order.
Flag: EXEMPT refactor
Change-Id: Iba4cb44203858cc3784d8f6886b400200deac36c