Add shaders re-implemented in HLSL

These were written against the shaders at revision eddd724e7.
There have been changes made since then, which will need to be mirrored.

See `data/hlsl/README.md` for the current status of each sample.

data/hlsl/texturearray/instancing.frag

@@ -0,0 +1,9 @@
+// Copyright 2020 Google LLC
+
+Texture2DArray textureArray : register(t1);
+SamplerState samplerArray : register(s1);
+
+float4 main([[vk::location(0)]] float3 inUV : TEXCOORD0) : SV_TARGET
+{
+	return textureArray.Sample(samplerArray, inUV);
+}