This fixes issue 11085 where a lot of changes were bolded when using
Polymer 2.
I could not find a reason why gr-change-list-item should have an
internal needsReview property and a _computeItemNeedsReview method.
In Polymer 2 an undefined change.reviewed value would result in the
needs-review attribute being added, even though gr-change-list may have
set the attribute explicitly (and correctly!) from the outside.
I have sent a question to the Polymer expert group about this, but I
think the outcome of competing computes inside and outside is undefined
at best. So the likely outcome is that we will just remove the internal
compute.
Bug: Issue 11085
Change-Id: I6d437562cb624e07454b8e32c0a051f8ef2ac182
2da1fb6524