Minor decoder optimizations, kernel fixes, cpu backend fixes

src/xenia/cpu/hir/label.h

@@ -26,6 +26,13 @@ class Label {
   char* name;
 
   void* tag;
+  // just use stringification of label id
+  // this will later be used as an input to xbyak. xbyak only accepts
+  // std::string as a value, not passed by reference, so precomputing the
+  // stringification does not help
+  std::string GetIdString() {
+	  return std::to_string(id);
+  }
 };
 
 }  // namespace hir