[turbofan] Support preserving of optimized code maps over GCs.
[turbofan] Support preserving of optimized code maps over GCs.

This extends the existing support for --noflush-optimized-code-cache
mechanism to the newly added context-independent code entry in the
optimized code map. Note that this machanism is still off by default.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/1220883002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#29415}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh