SF: Dump CompositionEngine layers and cleanup output

No code was calling compositionengine::Layer::dump. This adds a call,
and cleans up a few odd details about the output so it looks
reasonable.

Test: dumpsys SurfaceFlinger
Bug: 121291683

Change-Id: Iad524ddcd1fe99c0a1670a8ebb045ecbffd5b2eb
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index d028c59..f637284 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -4715,6 +4715,14 @@
         result.append("\n");
     }
 
+    {
+        StringAppendF(&result, "Composition layers\n");
+        mDrawingState.traverseInZOrder([&](Layer* layer) {
+            auto compositionLayer = layer->getCompositionLayer();
+            if (compositionLayer) compositionLayer->dump(result);
+        });
+    }
+
     /*
      * Dump Display state
      */