Rename IsDontDelete to IsConfigurable (and invert conditions)

src/property.h

Index: src/property.h
diff --git a/src/property.h b/src/property.h
index ab2dcef8081eb8441f118abd8d276c3b0ea282a4..f64f9df849f0ef5af68824c4a4ebe96edb4e3830 100644
--- a/src/property.h
+++ b/src/property.h
@@ -260,7 +260,7 @@ class LookupResult V8_FINAL BASE_EMBEDDED {
     return IsDescriptorOrDictionary() && type() == CONSTANT;
   }
 
-  bool IsDontDelete() const { return details_.IsDontDelete(); }
+  bool IsConfigurable() const { return details_.IsConfigurable(); }
   bool IsDontEnum() const { return details_.IsDontEnum(); }
   bool IsFound() const { return lookup_type_ != NOT_FOUND; }
   bool IsDescriptorOrDictionary() const {