Revert "Add VTS readback tests for buffer slot clearing"

This reverts commit d103cd682822807d956cfb65454085fa5817a5ba.

NOTE: This is not a full revert, it leaves the production code in place and only reverts the VTS test changes.

Reason for revert: b/262370410

Test: atest VtsHalGraphicsComposerV2_1TargetTest on Oriole
Test: atest VtsHalGraphicsComposerV2_2TargetTest on Oriole
Test: atest VtsHalGraphicsComposerV2_3TargetTest on Oriole
Test: atest VtsHalGraphicsComposerV2_4TargetTest on Oriole
Bug: 262370410
Change-Id: I336beb9f0ed81b305b26c6d8e9da70cfabe04bbd
diff --git a/graphics/composer/2.2/utils/vts/ComposerVts.cpp b/graphics/composer/2.2/utils/vts/ComposerVts.cpp
index a6dfcaf..d4f0281 100644
--- a/graphics/composer/2.2/utils/vts/ComposerVts.cpp
+++ b/graphics/composer/2.2/utils/vts/ComposerVts.cpp
@@ -126,23 +126,15 @@
     ASSERT_EQ(Error::NONE, error) << "failed to setReadbackBuffer";
 }
 
-void ComposerClient::getRequiredReadbackBufferAttributes(Display display,
-                                                         PixelFormat* outPixelFormat,
-                                                         Dataspace* outDataspace) {
-    ASSERT_EQ(Error::NONE, getReadbackBufferAttributes(display, outPixelFormat, outDataspace));
-}
-
-Error ComposerClient::getReadbackBufferAttributes(Display display, PixelFormat* outPixelFormat,
-                                                  Dataspace* outDataspace) {
-    Error error;
+void ComposerClient::getReadbackBufferAttributes(Display display, PixelFormat* outPixelFormat,
+                                                 Dataspace* outDataspace) {
     mClient->getReadbackBufferAttributes(
-            display, [&](const Error& tmpError, const PixelFormat& tmpPixelFormat,
-                         const Dataspace& tmpDataspace) {
-                error = tmpError;
-                *outPixelFormat = tmpPixelFormat;
-                *outDataspace = tmpDataspace;
+            display,
+            [&](const auto& tmpError, const auto& tmpOutPixelFormat, const auto& tmpOutDataspace) {
+                ASSERT_EQ(Error::NONE, tmpError) << "failed to get readback buffer attributes";
+                *outPixelFormat = tmpOutPixelFormat;
+                *outDataspace = tmpOutDataspace;
             });
-    return error;
 }
 
 void ComposerClient::getReadbackBufferFence(Display display, int32_t* outFence) {