Fix various issues caused by Vertex/Index buffer conversions (#3762)

* Fix various issues caused by #3679

- The arguments for the 0th dummy vertex buffer were incorrect - it was given an offset of 16 rather than a size of 16.
- The wrong size was used when doing `autoBuffer.Get` on a converted vertex buffer.
- The possibility of a vertex buffer being disposed and then rebound can rebindings to find a different buffer where the current range is out of bounds. Avoid binding when out of range to prevent validation errors.
- The above also affects generation of converted buffers, which was a bit more fatal. Conversion functions now attempt to bound input offset/size.

* Fix offset for converted buffer

Ryujinx.Graphics.Vulkan/BufferHolder.cs

@@ -386,8 +386,25 @@ namespace Ryujinx.Graphics.Vulkan
             _waitable.WaitForFences(_gd.Api, _device, offset, size);
         }
 
+        private bool BoundToRange(int offset, ref int size)
+        {
+            if (offset >= Size)
+            {
+                return false;
+            }
+
+            size = Math.Min(Size - offset, size);
+
+            return true;
+        }
+
         public Auto<DisposableBuffer> GetBufferI8ToI16(CommandBufferScoped cbs, int offset, int size)
         {
+            if (!BoundToRange(offset, ref size))
+            {
+                return null;
+            }
+
             var key = new I8ToI16CacheKey(_gd);
 
             if (!_cachedConvertedBuffers.TryGetValue(offset, size, key, out var holder))
@@ -407,6 +424,11 @@ namespace Ryujinx.Graphics.Vulkan
 
         public Auto<DisposableBuffer> GetAlignedVertexBuffer(CommandBufferScoped cbs, int offset, int size, int stride, int alignment)
         {
+            if (!BoundToRange(offset, ref size))
+            {
+                return null;
+            }
+
             var key = new AlignedVertexBufferCacheKey(_gd, stride, alignment);
 
             if (!_cachedConvertedBuffers.TryGetValue(offset, size, key, out var holder))
@@ -428,6 +450,11 @@ namespace Ryujinx.Graphics.Vulkan
 
         public Auto<DisposableBuffer> GetBufferTopologyConversion(CommandBufferScoped cbs, int offset, int size, IndexBufferPattern pattern, int indexSize)
         {
+            if (!BoundToRange(offset, ref size))
+            {
+                return null;
+            }
+
             var key = new TopologyConversionCacheKey(_gd, pattern, indexSize);
 
             if (!_cachedConvertedBuffers.TryGetValue(offset, size, key, out var holder))