With the introduction of the fast-cloning double fields in the CSA stub for
literals we forgot to check for deprecated maps. As a result every subsequent
IC-miss would have to migrate the objects from such boilerplates.

This CL makes sure we don't use the deprecated map when copying boilerplates,
thus restoring the original behavior.

Bug: v8:6211 chromium:728682
Change-Id: If9ea1e0c5c6fb4236cb7a82ea33306a600925ac3
Reviewed-on: https://chromium-review.googlesource.com/538677Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45981}