Keep track of how often textures/buffers are locked on the CPU

For the upcoming preserve attachment optimisation, which will keep buffers/textures locked on the GPU between executions, we don't want to preserve any which are frequently locked on the CPU as that would result in lots of needless waiting for a resource to be unlocked by the GPU when it occasionally frees all preserve attachments when it could have been done much sooner.  By checking if a resource has ever been locked on the CPU and using that to choose whether we preserve it we can avoid such waiting.

app/src/main/cpp/skyline/gpu/buffer.h

@@ -89,6 +89,9 @@ namespace skyline::gpu {
         int megaBufferTableShift; //!< Shift to apply to buffer offsets to get their megabuffer table index
         std::vector<MegaBufferTableEntry> megaBufferTable; //!< Table of megabuffer allocations for regions of the buffer
 
+        static constexpr size_t FrequentlyLockedThreshold{2}; //!< Threshold for the number of times a buffer can be locked (not from context locks, only normal) before it should be considered frequently locked
+        size_t accumulatedCpuLockCounter{}; //!< Number of times buffer has been locked through non-ContextLocks
+
       private:
         BufferDelegate *delegate;
 
@@ -214,6 +217,13 @@ namespace skyline::gpu {
             return SequencedCpuBackingWritesBlocked();
         }
 
+        /**
+         * @return If the buffer is frequently locked by threads using non-ContextLocks
+         */
+        bool FrequentlyLocked() {
+            return accumulatedCpuLockCounter >= FrequentlyLockedThreshold;
+        }
+
         /**
          * @brief Waits on a fence cycle if it exists till it's signalled and resets it after
          * @note The buffer **must** be locked prior to calling this