This relaxes the constraints of the optimized code map in order to be
able to update existing entries. It also simplifies the interface a
little bit. We can now insert an entry for a newly allocated literals
array together with previously cached context-independent code.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/1753213002

Cr-Commit-Position: refs/heads/master@{#34427}