When we specialize to the native context, we can replace loads of the
NATIVE_CONTEXT_INDEX in any known context with the appropriate native
context for that context. This allows us to constant-fold and further
optimize things like %reflect_construct, which are inserted by the
parser.

R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1697513003

Cr-Commit-Position: refs/heads/master@{#33965}