DescriptorArray::IsProperty-related cleanup.
DescriptorArray::IsProperty-related cleanup.

More minor changes related to property predicates:

 * Slightly simplify logic when handling hidden properties.

 * Make IsProperty usage more consistent in RemoveTransitions.

Review URL: https://chromiumcodereview.appspot.com/9352012

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@10617 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh