Reorder release fence attachment for non-threaded RE

Changes when release fences are attached to layers for non-threaded
RenderEngine to ensure that fences are added and fired in the same
hop to the main thread. This removes the dependency on legacy screenshot
code and prevents a deadlock where screenshot requests are blocked on
the main thread while the main thread is blocked on the previous
screenshot request finishing.

Bug: b/351894825
Test: atest SurfaceFlinger_test
Flag: EXEMPT refactor and for flag removal
Change-Id: If9d4134aba1106484f94231c5104a57a605147b8
diff --git a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
index 4dec5f6..81b929b 100644
--- a/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
+++ b/services/surfaceflinger/tests/unittests/TestableSurfaceFlinger.h
@@ -472,12 +472,11 @@
         ScreenCaptureResults captureResults;
         auto displayState = std::optional{display->getCompositionDisplay()->getState()};
         auto layers = getLayerSnapshotsFn();
-        auto layerFEs = mFlinger->extractLayerFEs(layers);
 
         return mFlinger->renderScreenImpl(renderArea.get(), buffer, regionSampling,
                                           false /* grayscale */, false /* isProtected */,
                                           false /* attachGainmap */, captureResults, displayState,
-                                          layers, layerFEs);
+                                          layers);
     }
 
     auto getLayerSnapshotsForScreenshotsFn(ui::LayerStack layerStack, uint32_t uid) {