[D3D12] Force early Z with DSV, fix blend disabled flag in rb_colorcontrol ignored

src/xenia/gpu/shader.h

@@ -607,6 +607,10 @@ class Shader {
   // Returns true if the given color target index [0-3].
   bool writes_color_target(int i) const { return writes_color_targets_[i]; }
 
+  // Returns true if the pixel shader can potentially have early depth/stencil
+  // testing enabled, provided alpha testing is disabled.
+  bool early_z_allowed() const { return early_z_allowed_; }
+
   // True if the shader was translated and prepared without error.
   bool is_valid() const { return is_valid_; }
 
@@ -655,6 +659,7 @@ class Shader {
   std::vector<TextureBinding> texture_bindings_;
   ConstantRegisterMap constant_register_map_ = {0};
   bool writes_color_targets_[4] = {false, false, false, false};
+  bool early_z_allowed_ = true;
   std::vector<uint32_t> memexport_stream_constants_;
 
   bool is_valid_ = false;