Fix stale entries in optimized code map.

Fix stale entries in optimized code map.

This fixes a corner-case where extending an optimized code map left
stale entries in the abandoned copy. This can cause havoc not only in
the heap verifier but also in the GC, because stale entries have not
been recorded when being trated weakly.

Note that this also pre-tenures all optimized code maps into old-space
because their lifetime is coupled to the SharedFunctionInfo anyways.

R=hpayer@chromium.org
TEST=cctest/test-heap/Regress514122
BUG=chromium:514122
LOG=N

Review URL: https://codereview.chromium.org/1277873002

Cr-Commit-Position: refs/heads/master@{#30047}