[D3D12] Experimental 2x resolution scale

src/xenia/gpu/d3d12/shaders/texture_load_32bpb_2x.cs.hlsl

@@ -0,0 +1,18 @@
+#include "texture_load.hlsli"
+
+[numthreads(16, 16, 1)]
+void main(uint3 xe_thread_id : SV_DispatchThreadID) {
+  // 1 thread = 1 uint guest texel.
+  [branch] if (any(xe_thread_id >= xe_texture_load_size_blocks)) {
+    return;
+  }
+  uint4 blocks = xe_texture_load_source.Load4(
+      XeTextureLoadGuestBlockOffsets(xe_thread_id, 4u, 2u).x << 2u);
+  blocks = XeByteSwap(blocks, xe_texture_load_endianness);
+  uint block_offset_host = XeTextureHostLinearOffset(
+      xe_thread_id << uint3(1u, 1u, 0u), xe_texture_load_size_blocks.y << 1u,
+      xe_texture_load_host_pitch, 4u) + xe_texture_load_host_base;
+  xe_texture_load_dest.Store2(block_offset_host, blocks.xy);
+  xe_texture_load_dest.Store2(block_offset_host + xe_texture_load_host_pitch,
+                              blocks.zw);
+}