This reverts commit 662aa425.

Reason for revert: Crashing on Canary
BUG=chromium:718891

Original change's description:
> Reland: [TypeFeedbackVector] Store optimized code in the vector
> 
> Since the feedback vector is itself a native context structure, why
> not store optimized code for a function in there rather than in
> a map from native context to code? This allows us to get rid of
> the optimized code map in the SharedFunctionInfo, saving a pointer,
> and making lookup of any optimized code quicker.
> 
> Original patch by Michael Stanton <mvstanton@chromium.org>
> 
> BUG=v8:6246
> TBR=yangguo@chromium.org,ulan@chromium.org
> 
> Change-Id: Ic83e4011148164ef080c63215a0c77f1dfb7f327
> Reviewed-on: https://chromium-review.googlesource.com/494487
> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#45084}

TBR=ulan@chromium.org,rmcilroy@chromium.org,yangguo@chromium.org,jarin@chromium.org
# Not skipping CQ checks because original CL landed > 1 day ago.
BUG=v8:6246

Change-Id: Idab648d6fe260862c2a0e35366df19dcecf13a82
Reviewed-on: https://chromium-review.googlesource.com/498633Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45174}