Add VTS readback tests for buffer slot clearing

Bug: 258196272
Test: atest VtsHalGraphicsComposer3_ReadbackTest
Test: atest VtsHalGraphicsComposerV2_2TargetTest
Change-Id: I95d24f9cf10d95e54bc228c02bedab9a8281cfd1
diff --git a/graphics/composer/2.2/utils/vts/RenderEngineVts.cpp b/graphics/composer/2.2/utils/vts/RenderEngineVts.cpp
index 1700b2a..254ff3b 100644
--- a/graphics/composer/2.2/utils/vts/RenderEngineVts.cpp
+++ b/graphics/composer/2.2/utils/vts/RenderEngineVts.cpp
@@ -83,9 +83,7 @@
 void TestRenderEngine::checkColorBuffer(std::vector<V2_2::IComposerClient::Color>& expectedColors) {
     void* bufferData;
     ASSERT_EQ(0, mGraphicBuffer->lock(mGraphicBuffer->getUsage(), &bufferData));
-    ReadbackHelper::compareColorBuffers(expectedColors, bufferData, mGraphicBuffer->getStride(),
-                                        mGraphicBuffer->getWidth(), mGraphicBuffer->getHeight(),
-                                        mFormat);
+    ReadbackHelper::compareColorsToBuffer(expectedColors, mGraphicBuffer, -1 /* fence */);
     ASSERT_EQ(0, mGraphicBuffer->unlock());
 }