graphics: make raw image synchronization an opt-in setting

tests/ShaderRecompilerComputeTests.cpp

@@ -14022,8 +14022,14 @@ public:
               "backing");
       RenderExecutorTestAccess::ResetBindings(executor);
 
-      for (const bool formatted : {false, true}) {
-        const uint32_t before = formatted ? 0x13579bdfu : 0x89abcdefu;
+      Require(name, "raw image synchronization default",
+              !Config::SyncRawImageBuffersEnabled(),
+              "raw image synchronization should be disabled by default");
+      for (const auto [sync_raw, formatted] :
+           {std::pair{false, false}, {true, false}, {false, true}, {true, true}}) {
+        Config::Load({.sync_raw_image_buffers = sync_raw});
+        const bool sync_image = sync_raw || formatted;
+        const uint32_t before = 0x13579bd0u | (uint32_t(sync_raw) << 1u) | uint32_t(formatted);
         constexpr uint32_t guard = 0x2468ace0u;
         constexpr uint32_t after = 0xa1b2c3d4u;
         vk::ClearValue clear{};
@@ -14065,8 +14071,9 @@ public:
                     buffer.range == buffer_size &&
                     buffer_bindings.images.empty() &&
                     texture_cache.GetImage(target.image_id).backing.state.layout ==
-                        vk::ImageLayout::eTransferSrcOptimal,
-                "target discovery did not precede the image-to-buffer copy");
+                        (sync_image ? vk::ImageLayout::eTransferSrcOptimal
+                                    : vk::ImageLayout::eTransferDstOptimal),
+                "image-to-buffer synchronization ignored its setting or formatted reads");
         auto readback = CreateHostBuffer(name, 2 * sizeof(uint32_t),
                                         vk::BufferUsageFlagBits::eTransferDst, {0, 0});
         const std::array copies{
@@ -14104,8 +14111,9 @@ public:
         scheduler.EndRendering();
         scheduler.Finish();
         Require(name, "buffer alias observes prior GPU contents",
-                ReadBuffer(name, readback, 2) == std::vector<u32>{before, guard},
-                "buffer acquisition copied stale guest bytes instead of the image");
+                ReadBuffer(name, readback, 2) ==
+                    (sync_image ? std::vector<u32>{before, guard} : std::vector<u32>{0, 0}),
+                "buffer contents did not match the selected image synchronization mode");
         DestroyBuffer(&readback);
         Require(name, "rendering after buffer acquisition",
                 ReadCachedTexel(name, context, target.image_id) == std::vector<u32>{after} &&
@@ -14114,6 +14122,7 @@ public:
                 "attachment rendering lost its new color or changed the untouched array layer");
         RenderExecutorTestAccess::ResetBindings(executor);
       }
+      Config::Load({});
 
       auto colliding_msaa_texture = array_texture;
       colliding_msaa_texture.fields[3] =