This introduces the {CodeDataContainer} as a container for all mutable
fields associated with a {Code} object. For now only the kind-specific
flags are moved, but more fields can/will be moved gradually. The goal
is to make all fields in the {Code} header be immutable eventually.

R=jarin@chromium.org
BUG=v8:6792

Change-Id: I2eeba893afaba877fb6117e1f18371898c3a175e
Reviewed-on: https://chromium-review.googlesource.com/732987Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48902}