Clear windows branch; preserve previous contents in win-old

tools/windows/gpu-target.json.in

@@ -1,6 +0,0 @@
-{
-  "schema": 1,
-  "architecture": "@D4R_GPU_ARCH@",
-  "wavefrontSize": 32,
-  "validation": "Compilation is not hardware validation; run the GPU diagnostics."
-}