[turbofan] Don't treat the hole NaN as constant inside the compiler.

src/compiler/access-builder.h

Index: src/compiler/access-builder.h
diff --git a/src/compiler/access-builder.h b/src/compiler/access-builder.h
index 94ed0f7edd3e59635e79013cf136963807056d71..50932ce06010efeaf7ea73c2eb0cbae03cea40c4 100644
--- a/src/compiler/access-builder.h
+++ b/src/compiler/access-builder.h
@@ -18,6 +18,12 @@ namespace compiler {
 class AccessBuilder final : public AllStatic {
  public:
   // ===========================================================================
+  // Access to external values (based on external references).
+
+  // Provides access to a double field identified by an external reference.
+  static FieldAccess ForExternalDoubleValue();
+
+  // ===========================================================================
   // Access to heap object fields and elements (based on tagged pointer).
 
   // Provides access to HeapObject::map() field.