RasterizerCache Redesign: Flush

flushing is now responsability of children caches instead of the cache 
object. This change will allow the specific cache to pass extra 
parameters on flushing and will allow more flexibility.

src/video_core/rasterizer_cache.h

@@ -37,9 +37,6 @@ public:
     /// Gets the size of the shader in guest memory, required for cache management
     virtual std::size_t GetSizeInBytes() const = 0;
 
-    /// Wriets any cached resources back to memory
-    virtual void Flush() = 0;
-
     /// Sets whether the cached object should be considered registered
     void SetIsRegistered(bool registered) {
         is_registered = registered;
@@ -158,6 +155,8 @@ protected:
         return ++modified_ticks;
     }
 
+    virtual void FlushObjectInner(const T& object) = 0;
+
     /// Flushes the specified object, updating appropriate cache state as needed
     void FlushObject(const T& object) {
         std::lock_guard lock{mutex};
@@ -165,7 +164,7 @@ protected:
         if (!object->IsDirty()) {
             return;
         }
-        object->Flush();
+        FlushObjectInner(object);
         object->MarkAsModified(false, *this);
     }