[stubs] CSA::LoadFixedDoubleArrayElement() is now able to do a hole check.

src/machine-type.h

Index: src/machine-type.h
diff --git a/src/machine-type.h b/src/machine-type.h
index aeb3579fd90bce261a77953a5ee11d9567cc4992..8c304b6882b1c5a93727011f60e15b0f84474256 100644
--- a/src/machine-type.h
+++ b/src/machine-type.h
@@ -62,6 +62,8 @@ class MachineType {
   MachineRepresentation representation() const { return representation_; }
   MachineSemantic semantic() const { return semantic_; }
 
+  bool IsNone() { return representation() == MachineRepresentation::kNone; }
+
   bool IsSigned() {
     return semantic() == MachineSemantic::kInt32 ||
            semantic() == MachineSemantic::kInt64;