There's no need to have different versions of the fairly complex
TransitionElementsKindStub just to avoid a single instance type
check at execution time (which is used to figure out the effective
length in case of JSArray objects).

R=ishell@chromium.org

Review-Url: https://codereview.chromium.org/2064993002
Cr-Commit-Position: refs/heads/master@{#36954}