In VisitArrayLiteral(), we stopped creating boilerplates during
compilation. This created a bug, because we'd emit an HStoreKeyed with an
ElementsKind based on the initial elements kind of the boilerplate. Since
boilerplates may transition as part of elements transition feedback, this can
lead to incorrect values (storing a smi in a double array).
BUG=chromium:606021
Review-Url: https://codereview.chromium.org/2000673002
Cr-Commit-Position: refs/heads/master@{#36408}