Perform native context specialization immediately after graph
construction (also after inlinee graph construction). This way
we can do unified inlining before we go to typing and typed
lowering. And we will get better typing due to constants and
(checked) type feedback.

R=mstarzinger@chromium.org
BUG=v8:4470
LOG=n

Review URL: https://codereview.chromium.org/1404123002

Cr-Commit-Position: refs/heads/master@{#31255}