shader_recompiler: Add support for lowering geometry passthrough

Reuses most of the existing code for generating the gl_Layer passthrough. Fixes geometry in Nier: Automata on GPUs without HW passthrough support.

src/shader_recompiler/host_translate_info.h

@@ -16,6 +16,7 @@ struct HostTranslateInfo {
     bool support_snorm_render_buffer{};  ///< True when the device supports SNORM render buffers
     bool support_viewport_index_layer{}; ///< True when the device supports gl_Layer in VS
     u32 min_ssbo_alignment{};  ///< Minimum alignment supported by the device for SSBOs
+    bool support_geometry_shader_passthrough{}; ///< True when the device supports geometry passthrough shaders
 };
 
 } // namespace Shader