Add test cases for SPV_KHR_shader_draw_parameters.

reference/shaders-msl/desktop-only/vert/shader-draw-parameters.desktop.vert

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+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    float4 gl_Position [[position]];
+};
+
+struct main0_in
+{
+    uint gl_BaseVertex;
+    uint gl_BaseInstance;
+};
+
+vertex main0_out main0(main0_in in [[stage_in]])
+{
+    main0_out out = {};
+    out.gl_Position = float4(in.gl_BaseVertex, in.gl_BaseInstance, 0, 1);
+    return out;
+}
+

reference/shaders/desktop-only/vert/shader-draw-parameters.desktop.vert

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+#version 450
+#extension GL_ARB_shader_draw_parameters : enable
+
+out gl_PerVertex
+{
+    vec4 gl_Position;
+};
+
+void main()
+{
+    gl_Position = vec4(gl_BaseVertexARB, gl_BaseInstanceARB, gl_DrawIDARB, 1);
+}

shaders-msl/desktop-only/vert/shader-draw-parameters.desktop.vert

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+#version 460
+
+out gl_PerVertex
+{
+    vec4 gl_Position;
+};
+
+void main()
+{
+    gl_Position = vec4(gl_BaseVertex, gl_BaseInstance, 0, 1);
+}

shaders/desktop-only/vert/shader-draw-parameters.desktop.vert

@@ -0,0 +1,11 @@
+#version 460
+
+out gl_PerVertex
+{
+    vec4 gl_Position;
+};
+
+void main()
+{
+    gl_Position = vec4(gl_BaseVertex, gl_BaseInstance, gl_DrawID, 1);
+}